Dry-Weather Gardening

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 21st reported “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 7th…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.

More

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.

 

Selecting Roses

Local garden centers offer bare root roses for sale at this time of the year. Roses sold as “bare root,” i.e., without soil, are dormant, so they have less weight for shipping, take less space for storage, and need minimal care and feeding. As a result, they are less expensive than roses in nursery containers.

Larger garden centers will stock scores of roses, so list your buying goals. For example, you might want a yellow rose that is highly resistant to diseases. Those factors, color and disease resistance, would help to focus on a short list. Then you could compare the details on the labels of the two roses to learn how they differ.

One difference could be the class of the rose, i.e., Hybrid Tea, Grandiflora, Floribunda, Climber, etc. Roses vary greatly in size across classes, and even within classes, so your new rose should be the right size for its intended location. Definitions of the standard classes are available from Weeks Roses. Browse to www.weeksroses.com, click on “Plants” and then on “Roses by Class.”

An important factor not on the label is the plant’s suitability for growing conditions at the specific spot you have selected in your garden for this rose. Roses typically require ample nutrients, very good drainage and a minimum of six hours of sunlight every day. In addition, some roses will grow better in the particular climate of the Monterey Bay area.

Local garden centers should stock only plants that will grow well in the area around their location, so one approach is simply to trust the center’s buyer.

If you happen to be buying roses while away from your home ground, or looking for a rose you remember enjoying in a different climate, confirm that it is suitable for your garden.

The Monterey Bay Rose Society has recommended roses for local gardens: browse to www.montereybayrosesociety.org and click on “Easy Roses.”

Weeks Roses has recommended roses for the Pacific Northwest Climate, which is north of the Monterey Bay area, but more appropriate than the other climates listed. (The climate of Portland, Oregon, the “City of Roses,” is like that of the Monterey Bay area, but with more rain.) Browse to www.weeksroses.com, click on “Rose Info” and then on “Climate Info.”

If you intend to buy several roses, you might want the American Rose Society’s “2014 Handbook for Selecting Roses.” Browse to www.ars.org, click on “Shop” then on “Books & Merchandise.”

After you have selected one or more roses for your garden, look to the American Rose Society for reliable advice on planting and caring for roses. Brose to www.ars.org., click on “Resources” and then on “Articles on Roses.”

Enjoy your roses!

Uprooting Plants

Recently, as I was digging up four boxwood shrubs, and cutting down a twelve-foot elderberry, I recalled that some gardeners dislike toppling mature plants or discarding healthy ones.

This is not about relocating plants. Certainly, there are situations in which a plant has outgrown its spot, or has failed to thrive because of a lack of sun or moisture or nutrition, or simply doesn’t look right where it is, aesthetically.

In such situations, assuming the plant is not too big to move, go ahead and transplant to a better location within your garden, or gift it to a friend. You and the plant and perhaps your friend will be happier.

We might ask, “When is it a good idea to decommission a plant?”

One justification would be that the plant is both unwanted (for any of several reasons) and too big to move without significant effort or expense.

Another justification arises when an unwanted plant is not too big to move, but no alternative location is available in your garden or in the garden of any friend.

The option that remains is to lift the plant with care and bring it to a garden exchange. These events are constructive and popular when someone steps up to the task of organization.

One should link to the local gardening network to learn when and where a garden exchange will happen. Join a club!

An important mindset when removing a plant is to avoid any sense of loss, and instead to recognize the opportunity to bring in a new and more interesting plant. Therefore, one should have (1) a replacement plant already in mind, (2) the confidence and knowledge to grow the replacement plant, and (3) the patience to let the plant to reach full maturity.

The four boxwoods (Buxus sempervirens) I dug up had been intended to frame a rose bed, but these common plants had grown large enough to block the view of the roses. I will replace them with miniature roses, to be selected.

The elderberry was an unknown species, a gift that I planted before I realized how big it would get, and before I decided to devote that section of the garden to California native plants. A Pacific Red Elderberry (Sambucus racemosa) might have stayed, but this shrub’s berries were not red, but black.

I will replace this shrub with a Silverleaf Manzanita (Arctostaphylus silvicola), a beautiful very gray, and very endangered shrub that is endemic to the nearby Zayante Sandhills. It is also called the Santa Cruz Manzanita. I found a specimen at the Yerba Buena Nursery in Half Moon Bay.  It’s in a one-gallon nursery pot, so it will need time to reach its mature height of eight feet.

Uprooting plants can release space for new botanical treasures.

More

Here’s a picture of the Silverleaf Manzanita, from the website of Las Pilitas Nurseries, a treasure trove of information on California native plants, as well as a great source of those plants. There are two locations: Santa Margarita (about 18 miles north of San Luis Obispo) and Escondido.

Arctostaphylos silvicola, Ghostly Manzanita with a beefly. This manzanita is native north of Santa Cruz.

 

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