Pruning Roses

The gardening subject with the most advice and the greatest anxiety is pruning roses. January is the right time of the year for this task (with some inevitable exceptions, which we’ll get to), so let’s review.

Close-up of Yellow Rose

Rose ‘Graham Thomas’

Gardeners have good reasons for being uncertainty about pruning roses.

The need for pruning arises from the gardener’s priorities, not the plant’s requirements. This is evident from the existence of wild roses and so-called “cemetery roses” that thrive for generations without the care of any gardener. Pruning and other forms of rose cultivation are intended to produce more blossoms, larger blossoms, more desirable plant forms, and healthier plants.

If all roses were the same, pruning would be a simple matter, but the genus Rosa includes over 360 species, some of which are in cultivation since at least 500 B.C. This botanical diversity complicates the task: several of these species respond better to some pruning practices than to others.

Several species have been hybridized extensively, and thousands of cultivars have been available. The cultivar, however, does not determine the preferred pruning practice; more important determinants include the species and the form.

Roses are generally described in three major classifications: wild (or species) roses, old garden roses, and modern garden roses.

Old garden roses typically bloom once on old growth each season and are cold hardy. They require only minimal pruning, which is done after blooming primarily to manage the overall size and shape of the plants.

For this column, we’ll focus on modern roses, which by most accounts began in 1967.

Modern garden roses are typically hybrids derived from the very old China roses. They are most popular in today’s gardens and characterized as blooming on new growth, and ever-blooming, i.e., they continue blooming throughout the growing season. They are not cold hardy and a hard freeze can kill branches or entire plants. In the Monterey Bay area, cold weather is not a significant threat to these plants.

Pruning these plants begins with removing dead wood, and any branches that are diseased, broken or crossing other branches. These “clean up” actions prepare for cultivation pruning.

Modern garden roses generally benefit from a hard pruning to stimulate the new growth that will produce blooms. This is done during dormancy before new growth begins. In the Monterey Bay area, the best time to prune these plants is in during January and February, so right now is a good time to begin your rose year.

“Hard pruning” has various definitions, with most ranging between one-third to one-half of the canes. One approach calls for removing one-third of the canes entirely, then cutting the remaining canes by one-half.

One intriguing approach to pruning modern garden roses is to simply cut the plant down to eighteen inches in height. Shearing a rose in this way has been claimed to yield the most foliage and blossoms.

The so-called classical approach to rose pruning involves cutting canes to one-third or one-half, cutting at 45-degree angle to an outward-facing bud, opening the center of the plant for optimal light exposure, and removing branches that are thinner than a pencil. This approach yields larger stems, longer stems, and larger blossoms.

Whether you use the classical or shearing approach to hard-pruning your modern garden roses, the important message is to prune them at this time of the year. They will respond beautifully in the spring.

Resolve to Become Fire-safe

California has a history of wildfires, and this year’s fires have been particularly fierce and damaging. Governor Brown has identified climate change as producer of fire dangers and described a future of more wildfires in the state.

Currently, Monterey Bay area residents are sympathizing with—and perhaps assisting—people in California’s northern and southern regions that are suffering significant losses from wildfires. They should also guard against the potential for wildfires in their own communities.

Good advice is available for protecting your home from external fire dangers.

Pre-fire management, which is the current jargon, includes reducing vulnerability to flying embers with tile roofs or roof sprinklers. Hardening your home in these and other steps is good practice when building, possible when renovating, and always less costly than having your home reduced to ashes.

Still, defensive landscaping is particularly important and cost-effective, and most relevant in this column on gardening. I have listed selected online publications at the end of this column. They describe more good ideas that could be summarized here, but here’s an overview of three basic concepts.

Provide Defensible Space

Landscaping that is close to the home should not support the movement of the fire. This includes spacing trees at least ten feet part when on level ground, and farther apart when the home is on elevated land.

Diagram of Defensible Space

Defensible Space Zones 1 and 2

The second level of defensive space extends to 100 feet around the residence. California’s Public Resources Code, Section 4291 requires these firebreak provisions for all properties that are near “any land which is covered with flammable material,” i.e., land covered by forest, brush or grass.

Current wildfires have demonstrated, however, that wind-driven embers can fly up to one mile during a wildland fire, so the practical need for defensible space applies to any residence within a mile of a wildfire.

Use Fire-resistant Plants

Within a home landscape’s defensible space, using fire-resistant plants adds to protection from fire. CalFire describes these characteristics of fire-resistant plants

  • Store water in leaves or stems
  • Produce very little dead or fine material
  • Possess extensive, deep root systems for controlling erosion
  • Maintain high moisture content with limited watering
  • Grow slowly and need little maintenance
  • Are low-growing in their form
  • Contain low levels of volatile oils or resins
  • Have an open, loose branching habit with a low volume of total vegetation

Succulent plants that several of these characteristics and can effectively slow or stop the spread of fire. Succulent plant specialist Debra Lee Baldwin recently described how succulents protected a southern California home that a wildfire threatened, as adjacent homes burned to the ground. Click here for her YouTube presentation.

There are many plants that resist fires to some degree. Large succulents are most effective. Baldwin recommends Paddle Cactus (Opuntia), Aloes, Aeoniums, Crassulas, and Sticks on Fire (Euphorbia tirucalli).

Avoid Flammable Plants

As the corollary to using fire-resistant plants, avoid flammable plants. These are plants that

  • retain large amounts of dead material within the plant,
  • produce a large volume of litter, or
  • contain volatile substances such as oils, resins, wax, or pitch.

The most common trees that have highly flammable content are Eucalyptus, conifers, and all brooms (which often invade open areas). These plants can grow close together, making them even more prone to burst into flame. Keep them at least 100 feet from your home.

If you have been searching for a timely and constructive resolution to pursue during the coming year, a good choice would be to make your landscape both beautiful and fire-safe.

Source: Fire Watch Company

On-line Resources

California Department of Forestry and Fire Protection (CalFire): Ready for Wildfire (2017)

Pacific Northwest Extension: Fire Resistant Plants for Home Landscapes (2006)

UC Cooperative Extension: Safe Landscapes (2009)

The University of California, Division of Agriculture & Natural Resources: Home Landscaping for Fire

Adding Roses to Your Garden

Rose season is upon us! New plants have arrived at most garden centers, and this is the right time to decide if your garden would benefit from the addition of a rose.

The array of available varieties can be overwhelming, so preparation can streamline the selection process and increase your post-purchase comfort.

As you assess your landscape’s need for a rose, decide whether you want a shrub, climbing, rambling, miniature, or standard (tree) rose. This choice could narrow your search dramatically, but if you focus on a shrub rose, you will find the largest number of choices.

Another classification system identifies wild roses, old garden roses, and modern garden roses. The online resource Wikipedia provides a very welcoming and orderly overview of the seemingly countless kinds of roses.

Hybrid tea roses are among the most popular kinds of the modern garden roses. Hybrid teas, which are widely available in garden centers, provide gorgeous blossoms in a wide and growing range of forms and colors and almost always a beguiling fragrance. Selection relies upon the individual gardener’s priorities, which might involve complementing the colors of the garden’s existing collection of roses.

Local Master Rosarian Joe Truskot particularly appreciates the hybrid tea rose ‘Maria Callas’, which is also sold as “Miss All-American Beauty.’ Truskot is the author and publisher of the Central Coast Rose Manual, a valuable and unique resource for growing roses in the Monterey Bay area. This book can be found at Alladin Nursery (Watsonville), Bokay Nursery (Salinas), River House Books (Carmel), and Bookshop Santa Cruz (Santa Cruz).

The adventuresome gardener might wish to explore the extensive world of species roses, which are plants that occur in nature, without help from humans. Depending on who is counting there are 100 species or more than 360 species. These are the true wildflowers of the rose genus, always with five petals in white, pink or red blossoms. They occur in diverse scents, foliage, hips, and autumn colors. They are valued in naturalistic planting schemes and for the minimal pruning requirements. They bloom on new wood, so they can be cut back after flowering.

The species rose most likely found in a garden center is Rosa rugosa, also known as the Japanese Rose. (“rugosa” means “wrinkled,” referring to the plant’s corrugated leaves). Rosa rugosas are also available in various cultivars and hybridized with other species.

My garden includes two species roses:

Rosa californica is a fine addition in several ways to my native California bed, but it tends to spread through underground runners and develop a thicket.

Rosa mulligani, a rambler that grows vigorously and produces twenty-foot branches and spectacular one-time summer displays of white flowers.

Rosa Mulligani

Rosa Mulligani

To explore the world of roses, visit these websites:

Wikipedia/Roses

Weeks Roses

American Meadows

Heirloom Roses

David Austin

Joe Truskot

Roses of Yesterday and Today 

The months of January and February are the best time to prune roses, according to Joe Truskot. Now is a good time to refresh your knowledge of this annual task, inventory your roses, sharpen your tools, and schedule your pruning session. You might also attend Monterey Bay Rose Society’s hands-on Pruning Clinic at the Santa Cruz County Fairgrounds, 10:00 to 12:00 on January 13th and 14th, 2018. Local rose experts will volunteer their practical experience with best practices in this process, which can add significantly to bloom production during the coming season.

Spiny Plants in the Garden

Some attractive succulent plants can be dangerous!

Agaves, in particular, are often armed with spines that challenge both creatures that threaten to eat the plant and gardeners with the best of intentions.

Agave 'Blue Glow'

A popular hybrid Agave ‘Blue Glow’

The spines of many agaves generally occur as wickedly sharp points at the ends of leaves. These are called terminal spines, or more technically spinose apical processes. Spines that occur on the edges of leaves are marginal spines or spinose teeth.

By either name, they amount to the plant’s formidable defenses as well as to its aesthetic qualities.

Other spinose structures on plants include thorns and prickles. Here’s a primer for keeping them straight:

  • Spines are modified leaves or parts of leaves and are found on most cacti and some succulents.
  • Thorns are modified branches or stems and are found on some trees (citrus, hawthorn, honey locust, natal plum, etc.) and shrubs (pyracantha or“firethorn”, bougainvillea, Silverthorn, etc.)
  • Prickles are derived from the epidermis, which is the single layer of cells that covers the leaves, flowers, roots, and stems of plants. An informal definition of a prickle is “any pointed, sharp plant part that isn’t where a branch or leaf would be.” The rose provides the most similar example of prickles, which are often incorrectly called thorns of the rose. Other examples are the pink silk floss tree (Ceiba speciosa) and the less common white silk floss tree (Ceiba insignis).

Gardeners who practice the Chinese art of feng shui probably should avoid spiny plants entirely, especially near the entrance to the home. These plants are thought to stop the flow of chi, the central life force.

Still, many gardeners regard agaves as attractive, despite or because of the spines that many agaves develop. There are a few strategies that allow gardeners to cultivate spinose agaves or cacti without becoming harmed.

Some gardeners will snip the plant’s terminal spines. This approach might be appropriate for plants that are very near walkways or readily accessible to small children, but gardeners so concerned about spiny plants should avoid them in favor of softer varieties.

The most basic defense strategy involves simply being careful and alert to the potential harm.

Some uncommon gripping and cutting tools can be helpful in removing dead leaves or weeding around such plants. One online source is http://cactuspruner.com. Amazon also offers German-made 17.7-inch cactus tweezers that are angled for convenient use.

When planting or transplanting dangerous plants, leather gauntlet gloves and a long-sleeved sturdy shirt provide good protection.

An inexpensive and functional tool for such tasks is a bath towel, which can be used to wrap the plant for safe lifting and transport.

For an interesting brief video on using a winch to transplant a large cactus safely, browse to youtube.com and search for “Repotting a Giant Golden Barrel Cactus.”

With preparation and appropriate tools, gardeners can handle spiny agave plants without acquiring scratches or puncture wounds, and with the enjoyment of their dramatic beauty and a great variety of colors and forms.

Gifting Garden Books

As we enter the season of giving, you might puzzle over finding gifts for gardening friends, or for that matter advising well-intentioned but stumped gift-givers what you might enjoy finding under your holiday evergreen.

Gardeners can always use another special plant or a great tool that works without a cord or spark plug, but a gardening book can be an excellent choice.

In selecting a gardening book as a gift, first considerations include quality of content and the recipient’s interests.

Gardeners I have met are typically fascinated by what other gardeners have done with their patch of soil, so books about —and tours of—other people’s gardens are perennial favorites. A new addition to this popular genre is Private Gardens of the Bay Area, by Susan Lowry and Nancy Berner, with photographs by Marion Brenner (The Monacelli Press, 2017).

The book’s title, of course, refers to gardens around the San Francisco Bay. There are many “bay areas,” but SF somehow has assumed ownership of that term. That’s not objectionable in this case because the Monterey Bay and San Francisco Bay areas have similar growing conditions. (Gardeners in the Chesapeake Bay area might feel differently.)

This book resonates with local gardening priorities because of its consistent and light-handed interest in sustainability, especially through lawn alternatives and drought-tolerant plants. The garden presentations convey these important messages subtly through multiple examples and without preaching.

The book takes the reader on an imaginary tour of thirty-nine gardens, which the book groups in four regions surrounding SF Bay. The gardens range in size from very small to very large, the gardeners range from dedicated amateurs to experienced designers, and the product compiles a wealth of ideas to inspire all gardeners.

The garden descriptions, averaging about six pages, understandably focus on each site’s exceptional vignettes, which are the most readily adaptable features for one’s own garden. Time is needed to add impressive mature plants to the garden but effective designs can be replicated with creativity and commitment.

Authors Lowry and Berner have written other books on private gardens; their communication skills are evident in each garden description. They introduce the gardeners, provide a bit of the garden’s history, characterize its design successes, and often highlight individual plants that contribute to the garden’s uniqueness. Their prose is non-technical and readable, and they also include botanical names of plants for those who wish to search for more information.

Marion Brenner’s photographs are beautifully done. Most of her images present aspects of the landscapes of interest while some show satisfying details of specific plants. The authors also credit Brenner as their guide to SF Bay Area gardens, drawing on her decades of experience in local garden photography.

Private Gardens of the Bay Area would be a fine gift to an avid gardener living in this part of California, or to others who would like to experience this horticultural paradise vicariously.

Happily, you can also choose from many excellent gardening books on a wide range of topics, assuming you what inspires your giftee’s gardening pursuits. The American Horticultural Society annually recognizes exceptional gardening literature through the AHS Book Awards. The winners for 2017 include the following:

  • All the President’s Gardens by Marla McDowell (Timber Press) —the White House gardens;
  • The Bee-Friendly Garden, by Kate Frey and Gretchen LeBuhn (Ten Speed Press) —plants for bees;
  • Garden Revolution, by Larry Weaner and Thomas Christopher (Timber Press) —ecological gardening;
  • Plant, by the editors at Phaidon Press (Phaidon Press) — fascinating botanical art; and
  • Rock Gardening, by Joseph Tychonievich (Timber Press) — photos and detailed info on this gardening style.

For more info, browse to the AHS Book Awards for 2017  and then click in turn through Gardening Programs, National Awards, and Book Awards. There are outstanding books for many gardening specialties, easing your efforts to cultivate just the right gift.

You have another opportunity to find selected gardening books as well as plants and other gifts at Norrie’s Gift & Garden Shop at the UCSC Arboretum. Norrie’s Holiday Open House will be open from 10:00 to 4:00 tomorrow, December 2nd.