Gardening in July

Posted on July 6, 2014 by tomkarwin

During this hot and dry month, the avid gardener should pursue seasonal tasks to keep the garden looking good and prepare for the change of seasons.

Irrigation should be a high priority to sustain plants that must have a ration of water during the drought. Pass by Mediterranean climate plants, which are accustomed to dry summers. A little moisture will perk up even these rugged individuals and extend their best days, but a better use of scarce water resources would target the garden’s thirstier specimens.

Roses, for example, could produce another bloom cycle during July if treated to a balanced fertilizer and watered deeply. Other candidates for regular watering are plants in containers, which can dry out fast. First confirm that your water usage is within current restrictions.

If your garden consists mostly of Mediterranean climate and succulent plants, this year’s drought should not cause alarm. On the other hand, if you have a thirsty lawn, consider replacing it with plants of the summer-dry persuasion. The same strategy would be appropriate for plants from tropical, riparian or boggy areas.

Blossoms to enjoy in July include gladiolus, agapanthus and fuchsia, and fragrant Oriental hybrid lilies, e.g., pure white ‘Casablanca’.

I am also enjoying blossoms of Chitalpa tashkentensis ‘Pink Dawn’ trees, which are crosses of catalpa and desert willow. They put on a show reliably around Independence Day, but opened a little earlier this year.

The Corsican hellebores (H. argutifolius) have finished their winter-to-spring display, and leaned down their bloom stalks to drop seeds all around. The seasonal task is to cut stalks to their bases to make room for the new growth, which has already started.

The tall bearded irises also have finished blooming for this year. They will look best after the flower stalks are cut down, the leaves fade, and the rhizomes enter dormancy. Every four years, during the period from mid-July to mid-September, dig and divide the rhizomes to promote blooming for net spring.

In July and August, plant autumn-blooming blubs, e.g., autumn crocus (C. speciosus and C. sativus), meadow saffron (Colchicum autumnale), and spider lilies: Lycoris squamigera with lilac or rose pink blooms and L. radiata with orange-red blooms.

Control cool-season annual weeds, currently going to seed: bindweed, chickweed, crab grass, knotweed, lambs-quarters, mallow, pigweed, purple deadnettle, groundsel, nettle, purslane, speedwell and spurge, as well as field grasses. Dispose of seeds in the green waste not in the compost bin! The invasive cheery yellow Bermuda buttercup (Oxalis pes-caprae) has already faded, leaving clusters of bulbs to sprout next spring.

Behind Schedule in the Garden

Posted on April 13, 2014 by tomkarwin

The garden does not wait for the gardener, but goes about growing, reproducing, aging and eventually dying whether or not the gardener meets the schedule of seasonal tasks.

My garden has proceeded this year on its natural cycle. As the weather has warmed, even the plants for which I should have cut back last year’s growth are producing abundant new growth

Salvias exemplify this failing. Best practice with salvias is to cut them to the ground in the late winter or very early spring, when new growth first appears. This practice rejuvenates the plant, and gives it a youthful look. When the pruning is done too late, it is very difficult to avoid cutting off the new growth and setting back the seasonal growth.

I cut back a few of the salvias in my garden, but left many more with their tired branches from last year.

Fortunately, perennial plants really do not depend on punctual gardeners. Salvias perform better when treated well, of course, but they will survive nicely even when neglected.

I was able to prune my roses at the right time. It is possible to let rose shrubs grow without annual pruning during the dormant season, but they will have a more compact form and produce more blossoms when cut back about one-third each year.

Fruit trees are another matter. Happily, I pruned my apple trees in a timely way: I cut back last year’s growth just before blossoms appeared on the trees. There are just four dwarf apple trees in my garden, but skipping this annual task would allow sprawling growth and reduce the yield.

I did not, however, spray my trees as recommended to discourage codling moths. I did read about the life cycle of those pests, and made life a little harder for the over-wintering larvae by raking the mulch away from the base of the trees.

Weeds also are responding well to our limited rain and the warming weather. They are growing very nicely! I haven’t identified all the several weeds that make my garden their home, but I can always spot the bright yellow flowers of sourgrass, which expands its territory in my garden each year.

Wikipedia (always helpful) has this comment about sourgrass: “Indigenous to South Africa, Oxalis pes-caprae, the ‘Bermuda buttercup,’ is an invasive species and noxious weed in many other parts of the world, including the United States (particularly coastal California)…”

Ideally, gardeners should pull this weed when it first appears, before it produces countless tiny bulbs. Sadly, I am behind schedule again this year.

This experience yields clear lessons for gardeners:

Strive to keep pace with Nature’s rhythm
Appreciate the ability of plants to thrive despite neglect, and
Take satisfaction in the seasonal tasks you do complete.

Enjoy your garden!

Several books on year-round gardening are available through your public library, your bookstore or online. For example, a search of the Amazon.co website for “gardening year-round” yields 45 pages of books to consider. Many of the books listed focus on edible gardening; several also include ornamental gardening.

Before investing your time or money in a gardening book, make sure that it has information for your gardening environment. The most useful gardening information for gardeners in the Monterey Bay area will be specific to USDA Plant Hardiness Zone 9. Information in books oriented to “northern California” or “Pacific Northwest” will need interpretation for gardeners in Zone 9. Books intended for other parts of the United States or the world could still be helpful, but should be treated like exotic materials.

Still, given that awareness, some classic books on year-round gardening written by English authors can be very much worth reading. Examples, include books by Vita Sackville-West, Beth Chatto and Christopher Lloyd.

Whether written by American or English gardening experts, the date of publication is not important: Nature’s seasonal patterns have not changed significantly.

Here are suggestions:

The Four-Season Landscape: Easy-Care Plants and Plans for Year-Round Color (A Rodale Garden Book) (1994), by Susan A. Roth (Author)

Golden Gate Gardening, 3rd Edition: The Complete Guide to Year-Round Food Gardening in the San Francisco Bay Area & Coastal California (2010), by Pamela Peirce (Author)

Gardener to Gardener: Almanac & Pest-Control Primer (2000), by Vicki Mattern and Fern Marshal Bradley (Eds)

A Yardscapes Year: Ideas and Plants for Bay Area Gardeners (1999), by Mia Amato

The Western Gardener’s Journal: A Three-Year Almanac (1998), by Margaret Moulton

Dry-Weather Gardening

Posted on January 25, 2014 by tomkarwin

Local weather patterns have been quite unusual, recently.

The Monterey Bay area had a short spell of cold, relative to our familiar moderate temperatures, followed by very dry and warm days. Now, much of central California is officially in “extreme drought,” and likely to remain in that condition for the next several weeks.

The National Weather Service has blamed the recent weather on “a strong ridge of high pressure in control along the west coast,” and on January 21^streported “all signs point to the ridge off the coast rebuilding for next week…this will lead to more above normal temperatures (more records will likely be set) with all of the rain staying to the north. Long range is trending more pessimistic for rain chances out to February 7^th…Unless there is a big shift in the pattern, this will go down as the driest January on record for almost all locations.”

The University of California’s Agriculture and Natural Resources specialists have recommended strategies for keeping edible and ornamental plants alive during this drought.

First, watch plants for signs of water-stress. The symptoms include

wilting or drooping leaves,
curled or yellowed leaves that fold or drop,
foliage that changes form green to grayish,
new leaves that are smaller than normal,
lawns that retain a footprint longer than usual.

Ornamental trees are generally in a dormant stage, at this time of the year, and will not require watering until they resume growth. One or two deep irrigations in the spring and summer will keep them healthy and resistant to diseases and insects.

Fruit and nut trees will require adequate moisture from bloom until harvest to produce a good crop. If that level of irrigation is not available, a few early-season irrigations will keep the trees alive, at least, although they might not produce much fruit.

Shrubs will need a thorough watering in the spring, and one or two more summer irrigations to be kept alive.

Most vegetables will need regular irrigation during flowering and fruit production. Squash, zucchini and other vines can be kept alive with irrigation once or twice weekly through the season.

Ground covers should be watered about monthly from April through September, with amounts related to local heat and dryness.

Lawns should be provided at least half the usual amount of water. Without adequate moisture lawns will go dormant eventually, but often can be revised with subsequent watering. Warm-season lawns (e.g., Bermudagrass, buffalo grass) are more drought-tolerant than cool-season lawns (e.g., tall fescue, ryegrass).

For now we can only wish for the overdue rain and water our plants at least minimally.

For the most up-to-date, authoritative information on local weather, click here to visit the website of the Western Region Headquarters of the National Weather Service. Click on “San Francisco Bay Area” for information that is closest to the Monterey Bay Area.

Multiply by Dividing

Posted on October 3, 2013 by tomkarwin

September calls us to divide our herbaceous perennial plants.

We divide these plants for one or two or three reasons:

First, the plant has become too large for its space, crowding other plants or even spilling into a walkway. When encountering such situations, remember to install new plants with their mature size in mind.

Second, the plant needs room to grow, produce blossoms and stay healthy. Many perennials need to be divided every three or four years, or will reduce blooming or become misshapen. Ideally, divide your plants when they are still at their best.

Finally, you want more of the same plant, either to place elsewhere in your garden or to give to friends. Dividing perennials yields new plants quickly and with little effort, and at lower cost than any other method except planting seeds.

Schedule a division project for cool weather, and water the plant in advance to make digging easier. Plan to replant the divisions soon, or prepare to store them in shade and kept moist.

Dig a trench around the plant, at the edge of the branches (the drip line). This will sever the longer roots cleanly, and retain the plant’s primary roots.

After trenching, dig under the plant from several angles, and lever the plant out of the ground. When dividing a large plant, slice from above to cut the root ball into two or four sections for easier handling. Re-fill the hole with compost.

Once the plant is out of the ground, decide whether to plant large or small divisions. Large divisions, e.g., halves or quarters, when replanted, will yield a full specimen in a single season. Many plants can be divided into many small plants that will grow quickly, but take longer to reach mature size.

In making this decision, remove the soil from the roots by gently shaking or washing, and examine their structure.

Perennial root types include offsets, surface roots, taproots, underground running roots, and woody roots. Dividing each of these requires a specific method that may be obvious upon inspection but for more about these methods visit ongardening.com.

Select healthy divisions for replanting or gifting. With perennial plants that develop a dead center, discard that section and choose divisions from the outer sections. Also discard any divisions that appear broken, weak or diseased, or that have minimal roots.

Plant the divisions where they will have their preferred exposure to the sun and space to grow to mature size. Dig a hole large enough to spread the plant’s roots, water in and keep moist until the rains begin.

Dividing herbaceous perennial plants can be a productive and satisfying project for the early fall.

Enjoy the season!

Fine Gardening magazine has posted Janet Macunovich’s helpful article on dividing perennials, including lists of specific categories of plants that should be divided in particular ways, as well as a few perennials that are best not divided.

The same magazine has posted a series of short video recordings that demonstrate methods for dividing perennials with different root types.

Bulbs for Next Spring

Posted on August 26, 2013 by tomkarwin

Now that the spring-blooming bulbs have enriched our gardens and faded away, it is time to prepare next spring’s display.

Spring-blooming bulbs should be lifted, divided and replanted every three or four years, so if your existing bulbs could stay in place for another year or two, you can take time off—or attend to other garden priorities that are waiting for attention.

If your garden is still a Spring Bulb Free Zone, or if you wish to bring new or additional bulbs into the picture, now is the time. Let’s review.

The Daffodil (Narcissus) is the most popular spring-blooming bulb. A multitude of great choices is available. The American Daffodil Society advises that there are between 40 and 200 different Daffodil species, subspecies or varieties of species and over 25,000 registered cultivars (named hybrids). These are divided among the thirteen divisions of the official classification system. Visit the ADS website, http://daffodilusa.org/, for full information on the divisions, which are the many delightful forms of the blossom. That website also has good advice on growing this garden favorite.

Visit Wikipedia (search for Narcissus) for fascinating (I think) information on sixteen selected species of Narcissus.

Another very popular spring-blooming bulb is the Tulip, which needs a chill period to grow well. The Monterey Bay area has insufficient cold days for Tulips, so plant pre-chilled bulbs. Most mail-order suppliers offer pre-chilled bulbs, and will ship them at planting time. Order early to be sure to get pre-chilled bulbs of the cultivars you prefer.

There are many beautiful spring-blooming bulbs beyond these favorites, so try other popular choices: Hyacinth, Crocus, Grape Hyacinth, Allium, Siberian Squill, Crown Imperial, Snowdrop, Anemone, and Freesia.

Planting spring-blooming bulbs begins with choosing a location that has full exposure to the sun and is well drained. Build a berm or raised bed to ensure good drainage. If your soil is heavy with clay content, dig in a generous, three or four inch deep layer of organic compost. Bulbs that will remain in place for the next bloom season also will benefit from a top dressing of a good compost material.

Plant the bulbs deeply: three times the height of the bulb. This works out to four-to-six inches to the bottom of the hole for a typical daffodil. Water them in and place mulch on the surface to retain moisture and discourage weeds.

Garden centers are beginning stock spring-blooming bulbs now. As always, the selection is broader when ordering from a catalog or on the Internet.

In next week’s column, we’ll consider opportunities for creative landscaping with spring bulbs.

More – Mail order sources for bulbs

Brent and Becky’s Bulbs – Spring/Fall 2013 Catalog

John Scheepers, Inc. – Beauty from Bulbs

Van Engelen, Inc. – Wholesale Price List

White Flower Farm – Fall 2013 Garden Book

Touring Local Greenhouses

Posted on June 22, 2013 by tomkarwin

Next Saturday, June 15^th, presents a fine opportunity for avid gardeners to satisfy their curiosity about the greenhouse business, and about growing flowers, herbs and other plants for commercial purposes.

The 4^th Annual Monterey Bay Greenhouse Growers Open House provides a unique educational experience, suitable for all gardeners, from novices to nerds.

Greenhouse growing is basically a straightforward and transparent process, but even inquiring minds will find much to absorb. There will be a rich flow of practical information about large-scale propagation, fertilizing, pest control, harvesting, as well as packing and shipping for the market. Most of the growers’ efficient, science-based practices are readily applied in home gardening environments.

At another level, visitor will gain insights into the commercial aspects of the business, including trending preferences for specific plants, flowers and herbs, seasonal variations, manipulating bloom times to meet market priorities, etc. It’s all quite interesting as a glimpse “behind the curtain,” even if you have no intent to engage in that field of endeavor.

There are six quite different greenhouses to visit during the day. You need not visit them all, and you may plan your own sequence of visits, from 10:00 a.m. to 4:00 p.m. The greenhouses are these:

California Floral Greens: baby eucalyptus, ivy, leather leaf, hydrangeas, parvafolia, kangaroo paw, flax, star asparagus, along with additional ornamental greens
California Pajarosa: 150 varieties of hydroponic roses: hybrid teas, sweethearts, and spray roses
Jacobs Farm: 60 varieties, including common and specialty herbs and an array of edible flowers
Kitayama Brothers: Cur flowers, including lilies, gerberas, lisianthus, snapdragons, calla lilies, iris, tulips, gardenias
McLellan Botanicals: Orchids, ranging from the popular (Phalaenopsis, Oncidium and Miltonia) to the exotic (Paphiopedilum, Cattleyas and other varieties), plus ornamental eucalyptus foliage.
Succulent Gardens: Over 600 varieties of succulents on display in the greenhouse and on the grounds, with many available for sale.

Also:

Garden writer Debra Prinzing will sign copies of her new book, Slow Flowers. She is the author of several books and numerous articles on gardening, a popular lecturer and president of the Garden Writers Association. She also will demonstrate flower arranging at 12:00 and 2:30.
“As the Globe Turns…” Display of the unique Succulent Globe, at the Succulent Gardens Open House. This ten-foot globe has succulent plants defining the world’s continents. Stunning! This year’s San Francisco Flower and Garden Show featured the Succulent Globe, which is now on permanent display in the Monterey Bay area.

The 4^th Annual Monterey Bay Greenhouse Growers Open House is a free admission event. For all the details and a map of the greenhouses, visit www.montereybayfarmtours.org. Alternatively, call (831) 274-4008 or email tours@montereybayfarmtours.org for up to date information about the tours.

Enjoy the tour!

Quick and Easy Gardening

Posted on April 15, 2013 by tomkarwin

When selecting a gardening book, look for content that aligns well with your needs and interests. That might seem like advice from Mr. Obvious, but it is easy to be drawn into material that is too specialized or too fundamental in terms of your gardening goals.

Many gardeners share an interest in low-maintenance gardening, so that is has become an inside joke for landscape designers and contractors.

In fact, several factors influence the level of effort that a garden requires. Certainly, landscape size and plant selection are significant contributors to the maintenance task.

Another very important factor that can impact the time and effort required is the gardener’s knowledge of gardening. Simply stated, if you know what to do and when to do it, your efficiency goes up, your error rate goes down and your successes multiply.

So, how does one acquire that knowledge? One way is to spend a lifetime with hands in the dirt and heightened awareness, but there are shorter roads to expertise.

If you regard yourself as a novice, you might enroll in Gardening 101, but such courses can be hard to find and time-consuming.

A good alternative is Sunset Publishing’s 2013 book: The 20-Minute Gardener: Projects, Plants, and Designs for Quick and Easy Gardening, edited by Kathleen Norris Brenzel.

Despite its title, this book does not present a schedule for gardening in 20-minutes a day, but does provide good basic information on many aspects of gardening, so that one could use his or her time efficiently and effectively.

The first 40-plus percent of the book deals with Setting Up Your Space; Quick Fixes; Inspired Ideas, Easy Projects; and Techniques. Many sections within this part of the book begin with an action verb: Choose Easy-Care Plants, Keep Plantings Accessible, Plant Seasonal Containers, etc. This style amounts to setting clear objectives, always a good first step in getting work done.

The next section, which equals nearly half the book’s pages, presents brief descriptions of plants. There are countless gardening books that list and describe plants (gardeners apparently love lists!); the value of this section rests on the shortness of its plant lists in each of several categories. In this way, the book focuses attention on garden-worthy, easy to grow plants, but minimizes the pleasures of discovering and trying less familiar plants.

Such adventures might not be the novice gardener’s highest priority.

The remaining pages provide useful information and a good index.

Overall, the book offers clear and reliable gardening advice that could help the novice gardener establish the knowledge base for low-maintenance gardening, and lead to productive and satisfying gardening experiences. The 20-Minute Gardener is valuable resource for the targeted readers.

Enjoy your garden!

Delightful Dahlias

Posted on March 30, 2013 by tomkarwin

Get ready for the annual tuber and plant sale by The Monterey Bay Dahlia Society, next Saturday, April 6^th, at the Deer Park Shopping Center, in Aptos.

The sale will open at 9:00 a.m., when there likely will be a line of eager dahlia growers looking for the latest hybrid introductions, or particular favorites, or specific colors to complete a landscaping design.

Or all of the above!

The dahlia, a native of Mexico, grows quite well in the Monterey Bay area’s moderate climate.

There are many varieties of dahlias, so selection of plants for your garden is the first task. A good and simple rule of thumb is to select varieties that please your eyes. Other approaches include selecting plants that have won prizes or that have blossoms of the color, form or size that you prefer.

Fortunately, there are excellent plant selection resources on the website of the American Dahlia Society < www.dahlia.org>; click on the link for “Dahlia Resources.” To view photos of dahlia blossoms, conduct a Google search for “dahlia plants” and click on “Images”

Tubers are specialized structures designed to store nutrients during a dormant season. Dahlias are stem tubers, which differ from root tubers, like potatoes. A stem tuber has one or more buds on the end that was attached to the old plant. These buds, called “eyes” are the plant’s growing points, so examine actual tubers to spot an “eye.” Even experienced growers can have difficulty recognizing an eye, but a tuber lacking an eye will not produce new growth, so look closely.

The ADS website also provides information on cultivating dahlias. The basic (and easy) method is to select a spot that enjoys at least six hours of direct sunlight every day, and good drainage. The time to plant is between “right now” and about mid-June. The top of the tuber should four-to-six inches below the surface (larger tubers are planted deeper) with the “eye” facing upwards.

Taller dahlias should be staked to avoid flopping. Install a stake near the tuber at planting time; pushing a stake into the soil later risks damaging the tuber.

If you prefer not decorating your new dahlia bed with bare stakes, install a short piece of plastic pipe next to the tuber, with the top just above soil level. Then, when the plant threatens to flop, insert a thin stake into the plastic pipe and tie the dahlia to the stake.

Snails enjoy snacking on dahlias, so as soon as new growth appears, apply non-toxic snail bait, such as Sluggo or Escargo. Gophers also find the tubers tasty, so plan to monitor for evidence of gopher activity, and have traps ready.

Enjoy your garden!

Gardening for the Future

Posted on December 22, 2012 by tomkarwin

During a period of cold and rainy days, and holiday season attractions (and distractions), it may be difficult to focus on gardening priorities and attend to necessary tasks. On the other hand, this could be a very good time to plan future directions.

In this column, we consider resolutions for the coming year.

Our resolutions often address immediate needs, e.g., weeding in a more timely and consistent manner, upgrading the landscape design, removing a tree or shrub that has evolved from asset to liability, or installing a long-overdue drip irrigation system.

Each avid gardener could develop his or her own list of resolutions that are certainly worthy and not to be dismissed. Today’s goal is not to discourage productive actions but to suggest the importance of the long view.

This column is inspired by a recent report that chemical pesticides are used more extensively in the United States now than ever before. See below for a link to “Pesticides: Now More Than Ever,” by Mark Bittman, New York Times, December 11, 2012. The author cites research evidence of the link between pesticide exposure and certain cancers and other health problems and negative impacts on the environment, and states that genetically engineered crops are leading to dramatic increases in the use of pesticides.

These data are particularly troublesome, given the recent defeat of a state proposition to label genetically modified organisms (fruits, vegetables and meats). This proposition lost 47% to 53%, when multinational food corporations spent $46 million in a campaign that claimed falsely that the proposition was “flawed” and would be costly to consumers. The Organic Consumers Association, an advocate of that proposition, points to several similar initiatives in other states, begins preparing for another vote in California, and insists it is only a matter of time before GMO labeling becomes law.

Residential gardeners can resolve to support reduced uses of chemical pesticides by applying only organic methods in their own gardens, buying organically grown groceries and supporting the labeling of GMOs, when another vote is scheduled.

So-called “conventional” gardening, which relies upon chemical fertilizers and pesticides, was introduced in the early 1940s, during World War II. Americans are only beginning to recognize its threats to human health and the environment.

Organic gardening methods originated hundreds or even thousands of years ago. These methods are attuned with nature, inexpensive to apply, and proven to be effective.

For more satisfying gardening in the short term, a good resolution is to bring new-to-you plants into your garden regularly. Countless options are available in garden centers, catalogs and websites. New horticultural treasures can add learning opportunities and rewarding experiences to your gardening activities.

If you think that pesticides are simply a good thing in the garden or the agricultural field, read “Pesticides: Now More Than Ever,” by Mark Bittman, New York Times, December 11, 2012.

For a good introduction to organic gardening methods, read Organic Gardening magazine which is available from magazine stands or the Organic Gardening website. This publication has been a leading advocate of this natural approach to gardening for decades. It offers its magazine, online information and several authoritative books from various publishers. Rodale’s Ultimate Encyclopedia of Organic Gardening is a classic in the field.

Guidance in purchasing organically grown foods is available from The Daily Green, which lists “The Dirty Dozen” (foods with the highest pesticide residue), beginning with apples. When these foods are grown with so-called “conventional” methods, they will have relatively high concentrations of pesticides. If you want to eat these foods, buy only produce that has been certified as organically grown. Federal regulations require that foods that are labeled as “organic are grown without the use of pesticides.

Consumer demands to label genetically modified organisms are sure to continue on a state-by-state basis, until such initiatives force federal requirements for such labeling.To follow the political battle, visit the website of the non-profit Organic Consumers Association. This is one of several organizations that are pressing this issue, with determination to succeed in the long run.

The Organic Consumers Association seeks to persuade the Natural Products Association to stop calling GMOs “natural.” The term “natural” when applied to foods has no federal definition or standard and should not be mistaken for “organic” foods.

Late-season New Growth on Roses

Posted on December 15, 2012 by tomkarwin

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.

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.