Garden Priorities for March

Despite our current, most welcome rains, we remain below the normal precipitation level for this time of the year and water conservation in the landscape continues to be important.

Conserving Water

For long-term conservation, plant California native plants or other drought-tolerant plants from the world’s Mediterranean climates. Succulent plants are increasingly popular for this reason, and for their varied forms, textures and colors, and low maintenance needs. (Desert conditions are not ideal for succulents: all need some water and quick drainage, and many enjoy partial shade.)

Shorter-term water conservation strategies include composting and mulching to retain water, using drip irrigation for efficiency, selecting vegetable varieties for low water requirements, eliminating seasonal weeds to reduce competition for scarce water, and irrigating only when plants need water. See “More” (below) for water conservation tips from Master Gardeners.

Fertilizing

Garden priorities for March include fertilizing trees, shrubs and perennials when they begin to show new growth.

For roses, give each plant two cups of a balanced fertilizer, i.e., 10-10-10 or 12-12-12, plus a quarter-cup of Epsom salts, two cups of alfalfa, and a half-cup of rock phosphate or bone meal.

There are differing views for fertilizing some plants. With bearded irises, for example, some growers recommend just a generous handful of a balanced fertilizer for each plant; others advocate low-nitrogen fertilizer, e.g., 6-10-10, plus bone meal and superphosphate. (The thinking is that adding more nitrogen could encourage root problems.)

Pruning

March is a good time for pruning still-dormant trees and shrubs, following recommendations for each plant. Here are examples from my garden:

Thin a large Wild Mock-orange (Philadelphus lewisii) by cutting about one-third of the larger branches to the base of the plant.

Shape a large Milkflower Cotoneaster (C. lacteus) by removing old, unproductive limbs and spindly branches, and generally lifting the canopy to provide more sunlight to the understory.

Renew Salvias by cutting old growth to the ground when the plants begin to show early spring growth. Another shrub that responds well to this treatment is the Tree Daisy (Montanoa grandiflora), from Mexico, which can grow up to ten feet high in one season. This annual treatment might seem drastic but the plants otherwise will become scraggly.

A good book on pruning is The American Horticultural Society’s huge “A-Z Encyclopedia of Garden Plants” (Revised edition, 2004), which briefly describes thirteen pruning categories and indicates which to use for each of 15,000 plants.

More

A thorough presentation on conserving water in the garden: “Guidelines for Managing Drought in the Urban Landscape,” was developed by Sonoma County Master Gardeners Susan Foley, Phyllis Turrill and Jerilynn Jenderseck, with input from Mimi Enright, Sonoma County Master Gardener Program Coordinator and Paul Vossen, UCCE Sonoma/ Marin Farm Advisor. (February 2014)

The following paragraphs, also from the Sonoma County Master Gardeners, provide brief recommendations for water conservation in the garden.

1. Compost, compost, compost! Add organic matter to the soil. If soil is sandy, the addition of organic matter allows the soil to hold more water. Organic matter also helps open up soil allowing roots to go deeper and find more water at lower depths if there is any. Higher soil nutrition helps plants produce better yields with the same amount of water. Avoid adding excessive amounts of nitrogen as this encourages lush leafy growth that requires more water to sustain.

2. Mulch, mulch, mulch! Mulch keeps soil cool, conserves moisture and reduces weeds. Use three to four inches on top of the soil. The larger the material size, the deeper layer you need to provide. Choose from straw, fallen leaves, hulls, shredded bark, grass clippings and newspaper. It is not advisable to use plastic sheeting as mulch because it deprives the soil of much-needed oxygen. Keep mulch two inches away from the base of the plant to avoid the possibility of rot. When hand watering, pull back mulch so that water goes directly into the soil.

3. Use a drip system. Learn about individual plant moisture needs and group plants that have the same need together on the same valve. If using in-line emitters in one-fourth inch tubing that use one-half gallon per hour per emitter and there is a length of ten feet with emitters spaced every foot, five gallons of water an hour is used on that section of tubing. Add up all drip lines to determine total water used. Install a timer. Install shut-off valves at the beginning of drip lines in order to turn them off when an area is fallow. Irrigate only as long as it takes to moisten the active root zone. Water, preferably, in the morning or in the cool hours of the evening so that soil stays evenly moist. Don’t forget the drip system once it is set up. Monitor and adjust it, as needed.

4. Be selective. Consider the water available to support crops through harvest, and grow only the amount and types of vegetables the family will consume. For example, plant two beds of vegetables instead of six; plant four tomatoes instead of ten. To get the most out of the water you apply, grow high yielding vegetables like beans, chard, mustard, eggplants, peppers, tomatoes, squash, quinoa and amaranth.

Do not grow crops that need consistent moisture. Examples include most brassicas (broccoli, cabbage, Brussels sprouts, kohlrabi, cauliflower and radishes), lettuce and other greens, beets, carrots and other root crops, celeriac, celery, leeks and onions. Avoid these unless a particular variety has been bred to need less water. Generally, cool season crops are not drought resistant and growing them during the heat of the summer requires lots of extra water to keep them cool.

Consider the following observations on which crops need the most water and when:

  • Some beans and sweet corn need considerable water to produce a good crop. Beans need water most when they are blooming and setting fruit.
  • Corn needs water most during tasseling, silking and ear development. Yield is directly related to quantities of water, nitrogen and spacing.
  • Peas need water most during pod filling.
  • Other vegetables, such as cucumbers and squash, and fruits, such as melons, need water most during flowering and fruiting.
  • Tomatoes, peppers and eggplant need water most during flowering and fruiting. (Note that after tomatoes set, they can do very well with reduced water).

After deciding what to grow, choose varieties that tolerate dry conditions. Look for the terms “drought-resistant” or “drought-tolerant” in seed catalogs or on plant labels (note that “heat-tolerant” refers to above ground air temperature and is not the same as drought-resistant or drought-tolerant). Even these varieties require water. Some water is needed to start seeds or establish a seedling, and to periodically irrigate the plant through the growing season. Selecting varieties that are described as “widely-adapted” in addition to drought-resistant and drought-tolerant also may be helpful.

5. Consider days to maturity. A crop needing fewer days to mature requires fewer irrigations before harvest (e.g., 62-day ‘Stupice’ vs. 85-day ‘Cherokee Purple’ tomato). Look for early-maturing or short-season varieties. Days to maturity will vary from one part of the country to another as well as from one microclimate to another.

6. Increase plant spacing. Spaced plants are not competing as much for water in the soil. Very deep, open soil or French intensive double dug beds allow vegetables to be planted closer together because the roots have more room to grow deeper and find water if it is present. Try increasing the spacing recommended in the SCMG “Vegetable Planting Summary,”iv by 50 percent or even doubling the spacing if you have room.

7. Eliminate weeds. Weeds compete for water. Be aggressive in removing them from growing areas.

8. Use light-weight row covers. Cover plants as a means to collect dew. Dew drops onto soil and keeps it moist. While using row covers can help prevent insect damage, look under the cover from time to time to monitor plant growth and check for unwanted insects trapped inside.

9. Use shade. Heat-sensitive vegetables can benefit from being planted where they receive some afternoon shade. Plant them underneath or behind taller plants or consider using shade cloth.

10. Use windbreaks. The moisture on leaf surfaces is dried by moving air, causing the plant to need more water. In coastal and other windy areas, windbreaks will help roots keep up with leaf demands.

11. Determine when it is time to water again. Use a soil moisture meter. Or squeeze the soil in your hand: if it sticks together, it is still moist; if it is crumbly and falls apart, it is time to water.

Pruning Apple Trees

Recently, I joined about forty home gardeners for a presentation on fruit tree care. The question & answer session was conducted by Oren Martin, manager of the Alan Chadwick Garden at UC Santa Cruz (www.alan-chadwick.org) and Matthew Sutton, owner of Orchard Keepers, in Santa Cruz (www.orchardkeepers.com).

The event was hosted by the Santa Cruz’s Probuild Garden Center, which has an impressive collection of bare-root fruit trees, so some questioners were interested in selecting, planting and first-year care of these trees. Others—including myself—wanted to know about pruning their existing trees.

Martin and Sutton emphasized the goals of pruning: to control tree height, allow sunlight and air to reach the center of the canopy, remove poorly place branches, and renew older branches. They described and demonstrated two basic kinds of pruning cuts.

Thinning cuts remove a branch completely, with no regrowth. These cuts open the tree to more sunlight, and create and maintain fruit buds. Thinning cuts should not be made flush, but should retain the branch’s collar, which is the tree’s defense against the invasion of microorganisms.

Heading cuts stimulate the branch’s growth, shape the tree’s structure, thicken branches, or induce lateral branching. These cuts remove the branch’s terminal bud, which produces a hormone (“auxin”) that inhibits the growth of lateral buds. This phenomenon is called “apical dominance.” Removal of the terminal bud stimulates regrowth at the bud below the cut.

Heading cuts vary with the amount removed from the branch. A heavy cut removes 50% of the previous season’s growth, while a light cut (leader tipping) removes less than 25% of that growth.

This session was helpful, but left much to be learned. UCSC experts will offer three workshops of value for home orchardists.

Fruit Trees 101: Basic Fruit Tree Care will be offered twice. The first will be on January 18, 2014 at the Sierra Azul Nursery and Gardens, in Watsonville. The second will be on January 25th, at the UCSC Farm. Each two-hour workshop will cost $40 for general public. For details, browse to the website of the Center for Agroecology and Sustainable Food Systems, or call 831-459-3240

Basic Pome Fruit Pruning, with a Focus on Apples and Pears, will be offered from 10:00 to 12:00 on Saturday, February 1st, at the UCSC Farm. Orin Martin and Matthew Sutton will advise on pruning your fruit trees to maximize health and production. The cost is $40 for general public, $30 for Friends of the Farm & Garden members. To register, visit http://pruningpome.bpt.me/, call 831-459-3240, or email casfs.ucsc.edu.

More

An excellent information source for home orchard gardeners is the University of California’s website, The California Backyard Orchard. The section on Pruning & Training complements this column; several other sections provide expert advice for other aspects of the care of home orchards.

Pruning Roses

There’s no need to rush outside to prune your roses, but now would be a good time to prepare for that annual process.

Start by identifying which of your roses are Old Garden Roses, and which are modern roses. The OGRs are once-bloomers, growing on their own roots, while modern roses, e.g., hybrid tea roses, are repeat bloomers, grafted on sturdy rootstock (often ‘Dr. Huey’).

There are numerous rose species, varieties and hybrids, but pruning methods differ greatly between the two broad groups: OGRs and modern roses. Briefly, OGRs bloom on old wood and are pruned in the late summer, after their bloom period and before they set buds. Generally, prune OGRs in a limited manner, removing no more than one-third of the bush.

In comparison, modern roses bloom on new wood, and are pruned more extensively during the winter months, before new stem growth and buds appear in the spring.

Modern roses are hybrids, typically with species that evolved in Asia, where winters are not harsh, so dormancy is related more to winter’s shorter days than to its lower temperatures. In the Monterey Bay area’s moderate climate, modern roses can continue to grow through the winter months without a period of deep dormancy.

Still, even a relatively light dormancy gives modern roses an important rest period, and pruning during this period promotes new stems and large blossoms.

This year, despite December’s record-setting warm spells, we can rely on short winter days to enable our roses to enter dormancy. Defoliation (stripping a rose’s leaves) encourages that process and reduces the potential for continued top growth.

With that background, prepare to prune your modern roses at any time during January or February. The basic techniques have been described and illustrated many times in books and websites, so rather than providing a capsule version of those techniques, I have listed print and online resources on my website, ongardening.com, for your reference.

I will repeat my recent suggestion to relocate your roses, as needed, during the same period. Prepare the new location by digging a hole two to three times as wide as the root ball you expect to have, to support horizontal root growth. The new hole should be only as deep as the existing root ball, to minimize settling of the transplanted rose.

We ready to transplant the rose soak the new location thoroughly. Then, soak the existing rose, lift a good-sized root ball from the bed, and plant it in its new location at the same level as it was in its old location. Water it in.

Now is also the time to select bare-root roses for your garden, so next week I’ll review rose selection and buying.

More

There are many websites with good, free information about pruning roses. Search for “pruning roses” to see several options. Here are some that I found helpful:

All-American Rose Selections

David Austin Roses

American Rose Society (scroll down to the articles on “Pruning Roses”)

If you would prefer a book, look for these more general pruning titles in your local library or bookstore:

Pruning Made Easy – How to Prune Rose Trees, Fruit Trees and Ornamental Trees and Shrubs, by H.H. Thomas (2013)

This book will be published early in February 2014:

Pruning Made Easy – The Complete Practical Guide to Pruning Roses, Climbers, Hedges and Fruit Trees, Shown in Over 370 Photographs, by P. McHoy

Pruning and Moving Plants

Recently, with access to few hours of youthful energy, I pursued my gardening priorities. They were a bit early in the dormant season but too productive to postpone. Here’s a short list to encourage improvements in your own garden for the spring.

An Overgrown Shrub

A Glossy Abelia (Abelia ‘Edward Goucher’) had grown to seven feet, with long gracefully looping branches. It was an attractive, well-placed shrub that was crowding smaller plants. I had it coppiced, i.e., cut to the ground, to promote re-growth in the spring. This severe pruning method renews trees, particularly oak, hazel, ash, willow, field maple and sweet chestnut. It also works well with multi-trunked shrubs.

Plants in the Wrong Places

The Giant White Squill (Urginea maritime), notable for a huge bulb, is common in the Mediterranean basin but rarely seen in the Monterey Bay area. It is easy to grow, and can be moved at almost any time. Years ago, I planted a four-inch bulb where I later decided to reserve for California Natives, so I wanted to move it to the Mediterranean area. The bulb, which had grown to about ten inches in diameter, was easy to transplant.

Another wrongly placed plant was a Twinberry Honeysuckle (Lonicera involucrata var. ledebourii), a California native. It had grown to about four by four feet, but in a place I later designated as the South Africa area, so it had to be moved. I learned that it too could be coppiced, so we cut it to six inches high and replanted it in the California Natives area. It could grow up to 10-to-12 feet high, so we placed it toward the back of a bed.

An Unruly Shrub

Wagner’s Sage (Salvia wagneriana) produces my favorite salvia blossom. The pink and white form has white bracts surrounding hot pink flowers, for a unique presentation. My plant grew rampantly to six feet high and ten feet wide. I had placed it in partial shade, where it thrived but didn’t flower very well. I also had failed to prune to maintain a smaller, denser form, so it had become rangy. Fortunately, it had also produced several seedlings. The solution was to shovel-prune the original shrub, transplant a couple seedlings to a sunnier spot for more blossoms, and schedule regular, late summer pruning for a more compact size.

Unwanted Shrubs

I have nothing against the Bigleaf Hydrangea (Hydrangea macrophylla), but I needed to move three of these Chinese or Japanese native plants to make room for the Twinberry Honeysuckle and other California natives. Lacking a good place for them, I coppiced and moved them into large nursery pots, for gifting to another gardener.

Consider seasonal improvements for your garden.

More

The Giant White Squill’s large bulb is proportionate to its leaves and its stalk of many florets (blooming in August). The bloom stalk can reach five feet in height.

Giant Squill - bulb

Giant Squill - planted

Giant Squill Blossoms

The Glossy Abelia responds well to severe pruning during the dormant season. The first  photo shows the result of coppicing a Glossy Abelia that had grown to seven or eight feet in height. The following photo shows the renewed growth of another Glossy Abelia that had reached a similar height, about six months after coppicing.

 

Abelia - coppiced

Glossy Abelia - renewed

Garden Priorities for Summer

Last week, regarding summer care of roses, I briefly recommended fertilizing monthly and responding promptly to signs of insect or disease problems. Those are constructive actions, but there’s more that can be done to help your roses to flourish!

Fertilizing roses in the summer is important if they show signs of nutrient deficiency, such as weak growth. Provide a light application of fertilizer with an emphasis on phosphorous.

Recall that fertilizer labels indicate the percentages of the three principal ingredients: N – nitrogen (promotes the growth of leaves and vegetation); P – phosphorus (promotes root and shoot growth); and K – potassium (promotes flowering and fruiting). I have used Dr. Earth’s Rose & Flower Fertilizer (5–7–2), but you could find other very good fertilizers at your local garden center. As always, follow supplier’s recommendations.

Yellowing foliage probably indicates an iron deficiency, which calls for spraying with a liquid iron supplement.

The most common pest of roses is the aphid, which suck the plants juices from buds, stems and the underside of leaves. They can be washed away with a forceful stream of water, or treated with a spray of insecticidal soap, such as Safer® Brand insect killing soap.

I routinely grow Society Garlic (Tulbaghia violacea), which has a garlicky fragrance that seems to confuse or distract aphids. It really works!

Weekly watering will keep roses healthy during the summer months. Water roses at ground level to keep foliage dry and avoid fungal diseases. Use organic mulch to minimize evaporation and discourage weeds.

Deadheading spent blossom will promote new blooms. Cut them off close to a close to a cluster of five leaves; some experts recommend cutting at the second five-leaf cluster, to encourage growth from a stronger stem.

Remove suckers at the base promptly. If possible, pull them off from the rootstock; otherwise, cut them below the soil surface.

***

Deadhead other spring-blooming plants. This practice improves the appearance of the garden, promotes new blossoms from many plants, and reduces the spread of seeds (which might or might not be desired).

Currently, I am deadheading two larger plants: Corsican Hellebore (Helleborus argutifolius) and Mediterranean Spurge (Euphorbia characias, subsp. wulfenii).

Here are Hellebores in full bloom, standing upright.

Hellebores-1 Hellebores-cu2

And here they are laying over:

DSC02465

Here are the Euphorbias, fading:

DSC02469 DSC02468

These plants are quite different but still have common characteristics: they both produce large, dense clusters of flowers on thick stalks that bend over as the flowers fade to drop seeds away from the base of the plant. Both also are prolific self-seeders, if allowed.

At the same time, they produce new growth that limits access to the base of the flower stems. I have found a telescoping pruner to be invaluable in this task. A “cut & hold” model would be ideal.

Enjoy your garden in the summer!

Garden Priorities for June

The Eighth Annual Garden Faire happens today, Saturday, June 22, in Scotts Valley’s Sky Park. There’s still time to fit it into your schedule: it continues to 5:00 p.m. plus music until 7:00. Find all the info at <thegardenfaire.org>.

***

Successful gardeners synchronize their work with the annual cycle of the plants. Here are some timely tasks for the month of June.

June is the ideal time to prune certain evergreen trees, particularly Arborvitae, Deodar Cedar, Hemlock, Pine, and Spruce. You could prune Atlas Cedar, Chamaecyparis, Fir, Juniper/Red Cedar, and Leyland Cypress at this time as well. This month is also the right time to pinch back the “candles” of whorl-branched conifers, e.g., pines, spruces and firs.

I have been trying to find time to prune four English Boxwoods (Buxus sempervirens ‘Suffruticosa’) in my rose garden: they are getting bigger than I like. The preferred time for that task is late winter to early spring, i.e., mid-February to about May 1st, when new growth begins. In fact, they can be pruned at any time in the Monterey Bay area, where we don’t have the prolonged cold weather that could damage freshly pruned boxwood.

It may be tempting to shear Boxwood with hedge clippers or an electric hedge trimmer, but that’s not good for the plant. Shearing can produce a formal shape but it stimulates surface growth that shades the interior of the plant, reduces air movement and interior leaf formation and leads eventually to the plant’s decline.

The better method emphasizes thinning. After removing any dead or broken branches, cut branches to open the interior of the plant to sunlight. This might create temporary gaps in the foliage, but they will fill in soon enough and the plant will be healthier for having had the opportunity to develop interior leaves.

It is important to decide why you want boxwood in your garden. If you want to achieve a formal look, or to create a topiary shape, shearing might be appropriate, but be aware of the plant’s need to have sunlight reaching its interior.

If you are more concerned with the plant’s vigorous good health, prune by thinning. This process takes more time than shearing, and yields a more natural-looking shrub that will enhance your garden in a less formal manner.

I’ll discuss other seasonal topics in future columns. The short message for rose care is (a) fertilize monthly during the summer months, and (b) respond promptly to signs of mildew, aphid, black spot or other insect or disease problems. Watch for the Rose Curculio (Rhynchites bicolor), which will punch holes through the buds of yellow and white roses. Handpick adults and destroy infested buds.

More

Here’s a link to an interesting discussion by Peter Deahl of The Pruning School, on pruning boxwood, with the emphasis on thinning rather than shearing.

From the same place, here are notes by Peter Deahl on pruning evergreens.

Reading the online advice of skilled gardeners can be helpful, but gaining hands-on experience is most valuable. Grab your pruners!

Spring Pruning

Pruning is among the most challenging tasks for many gardeners, so timely reviews of this topic may be helpful.

One of the three most important times of the year for pruning is right now.

Our plants grow with seasonal cycles, so here are the dates that gardeners should know:

  • Spring Equinox (1st day of spring)       March 20
  • Summer Solstice (1st day of summer)  June 21
  • Fall Equinox (1st day of fall)                  September 22
  • Winter Solstice (1st day of winter)        December 21

Let us say we’re at mid-spring, because we don’t need to be obsessive. This is time to prune shrubs that flower in early spring.

Here are a few popular members of this desirable group:

  • Saskatoon Serviceberry (Amelanchier ainifolia, a good choice for this area);
  • Slender Deutzia (Deutzia gracillis, a hydrangea relative with lots of white blossoms);
  • Hybrid Forsythia (Forsythia x intermedia, several good cultivars);
  • Beautybush (Kolkwitzia amabilis ‘Pink Cloud’, a deer resistant native of China);
  • Honeysuckle or Woodpine (Lonicera periclymenum, favorite of hummingbirds);
  • Lewis’s Mock Orange (Philadelphus lewisii, a California native; the genus name comes from the Greek word for “brotherly,” like the Pennsylvania city);
  • Common Lilac (Syringa vulgaris, the Descanso hybrids have been bred for mild winters);
  • Bridal Wreath or Shrubby Spiraea (S. x van houttei or S. japonica, butterfly magnet);
  • Doublefile Viburnum (V. plicatum tomentosum ‘Shasta’, great lacecap flower heads;
  • Weigela (Weigela florida, several selection of cultivars)(don’t call it “why-gee-li-a”),

Prune these shrubs soon after their spring blooms have faded, because the plant then will develop buds for the next season’s blossoms. Do not prune after the Fourth of July, because you will remove the new buds and won’t have flowers next spring.

Generally, maintenance pruning for these shrubs involves cutting to the ground about one-third of the oldest branches.

Spring Pruning of Roses

Late winter is still the usual time for major pruning of roses, but there are situations in which some mid-season pruning might be appropriate. In particular, if a rose has grown more exuberantly than you wanted, you could cut it back at this time of the year.

Many roses alternate between heavy flowering periods and rest periods. The timing guideline is to prune between bloom flushes, just so you are not removing blooms.

At this time, you should also remove any suckers, which are vigorous branches that grow from the rootstock of grafted roses and “suck” energy from the primary plant. If you think you have a sucker, make sure it is not a desirable new basal stem from above the bud union: look for differences in the leaves and prickles of the desired plant. Then, pull the sucker off so it won’t grow back; cutting just encourages re-growth.

Enjoy your garden!

 

(more to come)

Renovating a Fuchsia Bed

My garden includes a small collection of fuchsias in a northeast-facing bed, where the plants thrive in open shade most of the day, after a little morning sun. Large, very beautiful Bolivian fuchsias (Fuchsia boliviana), both red and white forms, provide the background and uncertain varieties of smaller upright (not trailing) fuchsias are in the foreground.

The bed also has a wonderfully fragrant winter daphne (Daphne odora ‘Marginata’), which thrives in the same exposure.

The bed also had—until quite recently—a licorice plant (Helichrysum petiolare), which has very attractive woolly grey-green leaves.

All the plants had become quite large and the bed was overly full of plant life, so I began a renovation project.

The winter daphne doesn’t like pruning and it had retained a nicely mounded form, so I left it alone for the present.

I soon decided, however, that the licorice plant had to go. It’s an asset, there’s another specimen elsewhere in the garden, and this bed should focus on different varieties of fuchsia. The licorice plant, which grows rapidly, has fleshy branches and shallow roots and was easily removed without digging.

Fuchsias flower on new wood, so to control their size they can be pruned heavily, down to six–to-ten inches. The right time for this pruning, and for installing new plants and relocating existing plants is the early spring, after which the plants begin what the American Fuchsia Society refers to as their “aggressive growth cycle.”

I appreciate the height of the Brazilian fuchsias, so I didn’t cut them down, but I did renew the smaller plants. A couple sessions of tearing out and heavy pruning transformed the bed from a botanical tangle to a sparse mini-landscape.

It became evident that the licorice plant had dominated the middle of the bed, the winter daphne had occupied one end of the bed, and the smaller fuchsias were clustered at the other end. Given the project’s good seasonal timing, I relocated three fuchsias and installed a new fourth plant to create a more even distribution within the bed.

My local garden center had just received a shipment of fuchsias in gallon cans, so I could take my pick from the new inventory. Several different plants were all labeled only as upright, medium size plants: the wholesale nursery accepts only orders for “assorted fuchsias,” with the effect of downplaying the unique identities of the several varieties. I like to record the genus, species and cultivar of each plant in my garden, but this practice makes that difficult.

In any event, my renovated fuchsia bed should look great in a few weeks.

Enjoy your garden!

Fuchsia boliviana (red form)

Late-season New Growth on Roses

At this time of the year, ordinarily, roses have entered dormancy. This status, characterized by stopped growth above ground, protects the rose from winter freezes and provides a rest period that supports the plant’s longevity and productivity. Hothouse roses subject to year-round harvesting of blossoms have shorter lives and fewer blossoms, compared to the typical garden rose.

During dormancy, the rose reduces its metabolism, holds its fluids and nutrients away from the stems and stores them the core of the plant. This is the rose’s defensive position, designed to avoid a possible freeze of liquids in the stems.

The plant continues to develop below ground: root growth continues during the winter months and is important for newly planted roses.

Gardeners in the world’s colder regions worry that an unusual warm spell in the late winter or early spring might cause their roses to “break dormancy.” The plants could produce new growth that would be killed by a late freeze.

In more temperate climates, such as the Monterey Bay area, roses could show new growth of leaves and buds in the early winter for the same reason: an unusual warm spell. The National Weather Service, reports that the Monterey Bay area is having such a warm spell this year: November’s average high temperature was about five degrees above the historical level. When the NWS reports December’s data, we might well see the same pattern.

In such cases, gardeners need to either let their roses develop such new growth, or proceed with seasonal pruning. Here are three issues.

First, the new growth might not survive the winter cold. If that happens, the plant will have wasted energy producing the new growth, but suffered no lasting harm. A rose has two inactive dormant buds at the base of each leaf that can activate to grow new canes or leaves.

Second, if the new growth survives, the rose will miss its opportunity to rejuvenate. This could have long-term negative effects on the rose’s life and blossom production.

Finally, a break from dormancy means that the plant is sending fluids into the stems, making it vulnerable to a freeze that would expand the fluids and cause splits and tissue damage.

The preferred response to a broken or delayed dormancy, then, is to help the rose to enter dormancy. The gardener can do this by removing all leaves from the plant. This action will halt photosynthesis and encourage dormancy.

Once the plant becomes dormant, the gardener could accomplish seasonal pruning during the dormant period, which will continue to the early spring, after the last date when frost is expected.

Scientists are virtually unanimous in agreement that human-produced carbon dioxide emissions are causing global climate warming. This change is having countless effects, and including new issues for gardeners.

Fortunately, roses are tougher than they appear.

More

As part of my research into rose dormancy, I visited the website of the American Rose Society, which has great information on many aspects of rose growing. I didn’t see discussion of the late-season new growth growth issue, so I clicked on the link, “Ask a Question About Growing Roses,” and asked my questions.

I received a quick response from AIS Master Rosarian Karl Bapst, a self-described “Rosenut.” His own website http://www.rosenut.com/ has a wealth of rose-growing information that I expect to visit often in the future.

I even quoted Karl (without attribution!) for the closing line of my column.

Rather than trying to summarize his detailed information, I am including our e-mail dialog below, with minor editing.

KARWIN

Roses in this area (USDA Zone 9a) should be dormant now (mid-December). Some people have started winter pruning, only to discover that their roses have new leaves, due to an unusual warm spell (possibly global warming) in November. This new growth probably won’t survive the colder weather in January, but what harm might be done to the plant by pruning when new growth is showing? Also, what harm might cold weather cause to a rose with spring-like new growth in December?

BAPST

In your area, I doubt your winter temps will drop down far enough to damage any new growth. New growth has lots of sugar that acts as natural antifreeze. In my area, zone 5a, mid-spring temps can drop to the mid to low 20s and new spring growth is seldom affected. If it is affected, new growth occurs to replace it.  Keep in mind there are two inactive dormant buds at the base of each leaf. If that new leaf should die, one or both of the buds activate growing new canes or leaves. So, should any new growth be damaged by temps below the mid 20s, it’ll soon be replaced.

We often have new growth before we prune in spring. The rose bushes do just fine. I’ve pruned as late as late April and early May (due to inclement weather or illness) after the bushes are leafed out with no bad results. The roses even bloom at their normal times.

Roses are tougher than they appear.

KARWIN

I have sent in my column today with recommendations based on your advice, but I have a follow-up question. Last night, a Consulting Rosarian recommended responding to this new growth by defoliating the plant to encourage dormancy and completing seasonal pruning. (Most people around here prune between mid-December and mid-January.)

Comments?

BAPST

In warmer growing zones where there may not be natural dormancy, removing the leaves will promote a period of dormancy when the daylight shortens and temperatures moderate as we approach the winter solstice. Roses don’t naturally go dormant and will grow all year if conditions are right.

Modern roses bloom best on new wood, pruning promotes new wood so one gets more and bigger blooms. In my zone 5, winter’s cold and gloomy overcast skies, freeze and kill the leaves. Most stay on the bush until new growth or pruning removes them. The frozen soil and canes causes all growth to stop until conditions improve in late winter or early spring. Summer cutting of roses is pruning. You’ve noticed that cutting a bloom in summer causes a new cane to develop, usually from the base of the leaf under the cut. This occurs after your December/January pruning but on a larger scale.

Should you fail to prune or cut back then, any blooms produced on the un-pruned bush will normally be smaller and fewer on shorter canes. You’ll notice, though, any blooms will come from those short new growth canes. Even blooms that grow from the old cane tips will be on new growth.

In my area, we have no choice. When removing winter die-back or damaged canes, we force new cane growth. Often, especially on hybrid teas, which are naturally very winter-tender, removing die-back requires pruning almost to the ground. These bushes will bloom in late May/early June and will have grown to full size by July.

Understand, Old Garden Roses (OGRs, once-a-year blooming roses) bloom on old wood and buds are set the previous fall. Pruning on OGRs is done after they bloom or these buds would be removed when pruning. Should you get any questions from people asking why their roses don’t bloom it’s usually due to them pruning too early on Old Garden Roses.

KARWIN

I read a variety of online material in preparing this column, and found various pieces of relevant information.

For example, here’s an interesting point for the eHow.com website:

“Most rose plants that are capable of dormancy will not naturally initiate this process in response to cold weather. Most rose plants which are domestically grown in North America are hybrids with breeds of plants that evolved in Asia (most roses are Asian and are crossbred for their desirable characteristics, such as smell and appearance). Asian winters are not as harsh and, thus, dormancy in Asian roses is an evolved response to a lack of light. This can create problems for such roses in North America, where a cold winter can still supply enough sunlight to encourage the plant to keep growing.”

Such subtleties can be challenging for a garden writer with a deadline, and impossible to explore in a single column. I made no effort to explain the role of winter light in promoting or discouraging dormancy.

Pruning Lavender

Pruning chores can frustrate gardeners when they are unsure of their knowledge. While they might understand that pruning improves the plant somehow, after they have devoted time and energy to growing the plant, trimming the plant’s growth might seem counter-productive.

Pruning the lavender plant puzzles many gardeners, so let us take a look at best practices.

We prune lavenders to stimulate new green growth, which produces flowers, and to slow the formation of older woody growth, which does not produce flowers. Traditionally, we prune lavenders to compact mounding forms that look attractive and yield maximum blooms.

There are two good times of the year to prune lavender plants: in the early spring, before they begin seasonal growth, and in the late summer, after their bloom period. Fall begins on September 22nd, so now is pruning time.

Here is a way to confirm that your lavender is ready to prune. Take a break in the garden, sit quietly near your lavender plant(s) and watch the bees. If they flit from blossom to blossom without lingering to feed, you will know that the blooms are finished for the year and it is pruning time.

Pruning shears will do the job, but use hedge shears to make quick work of pruning. When pruning several lavender plants, an electric hedge trimmer will be the tool of choice.

In any case, ensure that the pruning tool is sharp enough for clean cuts, and wipe it down between plants with rubbing alcohol or bleach to remove any harmful bacteria or germs.

When pruning, remove about one-third of the green growth to stimulate new growth. Do not cut into the woody stems: they will not produce new green growth and cutting too deeply could kill the plant.

If you have the time and patience for precision pruning, cut just above the third node above the woody part of the stem. Most gardeners will keep this rule of thumb in mind without actually counting nodes on each stem.

This process should be repeated in the early spring.

Start this twice-yearly pruning schedule when the plant is still young, i.e., the second year after putting a new plant in the ground. This delay allows time for the plant to establish its roots.

Gardeners might encounter a lavender plant that has not been pruned routinely for three years or more and has become rangy and unattractive, with long woody stems and minimal blossoms. Sadly, the plant cannot then be pruned to rediscover the preferred tight mound form, and should be replaced.

With these guidelines, the gardener will find pruning lavenders quick and easy, and finish the task with a nice fragrance from the lavender’s aromatic oils.

Enjoy your lavender!

More.

There are minor differences in pruning recommendations for the various species of lavender. For this reason, the gardener should be aware of the particular species that is to be pruned.

The most popular species of lavender for residential gardening are English Lavender (Lavandula angustifolia), French Lavender (L. dentata)  and Spanish Lavender (L. stoechas).  Another form that may be seen is Lavandin or Hedge Lavender (L. x Intermedia), which is a cross (hybrid) of English Lavender and Spike Lavender (L. latifolia).

English Lavender’s flower petals unfurl along much of the length of its long stocks. Its green, narrow leaves largely lack the silver and gray cast of the other varieties. It is available in several cultivars. Sunset’s Western Garden Book lists the following: Alba, Blue Cushion, Buena Vista, Compacta, Hidcote, Jean Davis, Lady, Martha Roderick, Melissa, Munstead, Rosea, and Thumbelina Leigh. A light pruning after early-summer flowering often will promote reblooming later in the summer. In late summer, cut back to one-third or even one-half of stem length, as outlined above.

French Lavender has looser-looking, light purple flowers. Their grayish leaves appear more serrated (or dented) than those of their Spanish cousin (the specific name dentata means “toothed”). Prune after flowering remove about one-third of stem length.

Spanish Lavender has tight, deep purple blooms that are shaped like pine cones. Four petals reach skyward, distinctly shaped like rabbit ears. The flower spikes are highly compressed and surmounted by showy, large, sterile bracts. Some varieties have white flowers. The bushes grow about 18 inches tall, with silvery-green leaves. Cultivars include Hazel, Kew Red, Otto Quast, Willow Vale, Wings of Night and Winter Bee.

Hedge Lavender cultivars are Abrialii, Dutch, Fred Boutin, Grosso, Provence, Silver Edge, White Spikes, and others.