Tag Archives: pruning tips

How to Live in Peace with a Wisteria

A wisteria is one of those plants that you either love or dread. One of nature’s most resilient survivors they are able to withstand and recover quickly from difficult conditions. To some they are a little too tough for their own good with a growth rate rivaling bamboo during the summer. If you dream of a wisteria-covered pergola shading your patio here are some maintenance tips that are sure to keep both gardener and vine happy.

Wisteria at Filoli Gardens in Woodside

Wisteria are so vigorous they can be pruned at any time, keeping them in bounds and to clear out unwanted or dead growth. Prune out any stems you see extending into eaves, windows or shingles. If yours has gotten away from you, you can even prune it down to the ground and start over with training although you’ll have to wait a few years for your vine to bloom again.

To their control size major pruning is done during the dormant season. Start by trimming the long tendrils that grew over the summer back to about 6 inches from the main trunk. Cutting the tendrils back in this way will initiate flower bud development, neaten the plant up, and show off the attractive trusty, gnarly character of the vines.

Pruning during the dormant season will also give you a fighting chance of keep your wisteria from getting into mischief. As you know if you have a wisteria, those long tendrils are capable of growing another 25 feet during the summer.

Wisteria shading a patio

Whatever time you do renovation pruning remember the response of the wisteria to aggressive pruning is to literally explode with new runners. They put energy into new vegetative growth at the expense of flowering. Make sure you keep up on ongoing maintenance pruning by removing all unwanted runners right to their point of origin. Then prune back the others to 3 buds or sets of leaves. Repeated pruning of these runners is what will eventually give you spurs of wood, short laterals that in turn will provide you with flower clusters. You need to prune these runners all season long which ends up being every 3-4 weeks.

Do not fertilize your wisteria. They do not flower well is there is an over abundance or luxuriant growth. Over feeding also ends up giving them the means to become un unmanageable monster. If you find the wisteria vine has invaded a nearby bed, cut roots with a shovel below the soil line to control any that have wandered.

Maintaining a wisteria requires some diligence but the reward is worth the effort. Remember this especially during winter pruning season to make summer maintenance easier.

Cooke’s Purple wisteria

Which variety of wisteria should you get to cover your arbor, pergola, tree or other structure?

Chinese varieties such at ‘Cooke’s Special’ has clusters of fragrant blue-purple flowers 20 inches long. This variety can re-bloom which makes it a favorite.

Japanese wisteria ‘Caroline’ blooms early with mauve flowers. ‘Royal Purple’ (also known as ‘Black Dragon’) has sweetly scented dark purple flowers. Japanese wisteria are most effective when grown on pergolas so the long flower cluster can hang freely.

Silky varieties produce a profusion of short, 6 inch, fat clusters of strongly scented flowers that open all at once. They have velvety seed pods and bloom best in full sun.

 

Garden Tasks-Rain or Shine

Those of you who lived in the Santa Cruz mountains during the winter of 1982 remember it well. Following two days or torrential rains, a large section of hillside above Love Creek gave way. Thirty homes were destroyed and ten people were killed by the slide. The rainfall totaled 111 inches that year.

Rain gauge on 2/8/17 showing 99.99″ +10″ more as of 2/18/2017

During the winter of 1997 the San Lorenzo Water Department recorded 90 inches of rain. The department’s historical rainfall data goes back to 1888 and shows that during the winter of 1889 a whopping 124 inches of rain fell. This winter is one to rival the books with about 70-110 inches of rain falling so far depending where you live. We don’t aspire to break any records.

How does this much rainfall affect our gardens? If you have addressed drainage issues and are slowing, spreading and sinking all this water, congratulations. But what about the plants? Fortunately most plants are dormant or semi-dormant at this time of year. Even plants that don’t lose their leaves aren’t in growth mode yet. When a plant is actively growing either roots or new foliage it will suffer if the roots are soggy day after day. Fungal problems and root rot will take its toll on a plant. An extremely wet March or April is not a good thing.

We gardeners are the eternal optimists and hope that only gentle rains will fall through May. And during those lulls in the weather this is what I’m going to be doing over the next month.

California fuchsia – zauchneria californica

Prune fruit, nut, shade trees and deciduous vines like clematis. Cut back woody shrubs like Mexican bush sage, artemisia and butterfly bush to stimulate lush new growth. You can cut back these plants close to the ground. Don’t use this approach on lavender or ceanothus, though. Prune them lightly after blooming without cutting into bare wood.

Prune fuchsias back by a third and remove dead, crossing branches and interior twiggy growth. Container fuchsias can be cut back to the pot rim.

mophead hydrangeas in June

Cut back hydrangeas stems that bloomed last year and apply a soil acidifier if you want the flowers blue. Although sulfur is the traditional favorite for quickly acidifying soil it is not as kind to many beneficial soil microorganisms. Coffee grounds, pine needles, peat moss and cottonseed meal are better for your soil.

I’ll wait to prune back perennials that may have their new foliage damaged in a late frost. Already damaged foliage can protect a plant from further frost damage. Mid-March is the estimated date of last hard frost in our area. Or at least it used to be.

Don’t cut back grasses yet if you get frost in the area where they grow. Wait until mid-March. If you live where you rarely get frost go ahead and prune these plants back now. I’m going ahead and pruning California fuchsia, salvia ‘Bee’s Bliss’ and hummingbird sage now. They look terrible.

camellia sasanqua

Don’t prune spring flowering shrubs and trees like lilacs, flowering cherries, plums and crabapples, rhododendrons, azaleas, camellias, weigela or spirea until after they flower. You can cut some branches during flowering to bring in cuttings for bouquets.

I can tell that spring will soon be here as the flowering plum buds are showing color. Can’t tell from the weather report, though.

About Roses

Roses are the flower of love. Many of us have fond memories of favorites in our mother’s garden or of a beautiful bouquet given or received on Valentine’s Day. It’s dormant season for roses which is good for both pruning and adding a few to the garden.

David Austin rose

As a designer I have clients who have inherited roses and want to keep them as a remembrance. Others want to create a cutting garden filled with roses and other perennials. Don’t feel guilty for growing those beauties in your own garden. They use less resources than you think and there are many ways to grow them sustainably.

Roses, whether bush types, climber or ground cover carpet varieties, use a moderate amount of water in order to thrive according to the latest Water Use Classification of Landscape Species (WUCOLS) list. This amount of summer irrigation is the same as many of the plants on the list of Scotts Valley Water District’s 800 Approved Low Water-Use Plants for lawn replacement. Plants such as Emerald Carpet manzanita, Joyce Coulter ceanothus, Siskiyou Blue fescue grass, Pacific wax myrtle, butterfly bush, yarrow hybrids and Tapien verbena have similar water requirements.

Since now is the time to prune your roses here are a few tips.

Strike it Rich hybrid tea rose

Prune shrubs moderately to keep them compact. The goal is to keep the center of the plant open for good air circulation aiming for a vase-shaped bush with an open center. Cut out canes that cross, appear weak or are diseased, spindly or dead. Healthy canes appear green or reddish while old and dying canes are brown. Cut back the remaining stems by about one third. When pruning, cut canes at a 45-degree angle just above an outward facing leaf bud or a swelling on the cane. Clean pruners after every use to prevent the spread of disease and keep your pruners sharp.

Prune heirlooms roses such as David Austin and other old antique garden roses less because their open look is part of their charm.

Same goes for climbing roses. Cut out extra stems if there are too many and also cut back long established canes to about the place where they are slightly thicker than a pencil. Then cut each side stem down to several inches. This will make the cane flower along its complete length for a beautiful spring display.

Zepherine Drouhin climbing rose

Pluck off and rake away any old leaves. They can spread fungal spores. Consider spraying dormant plants with a combination of organic horticultural oil and copper soap or lime-sulfur. If you usually only have problems with black spot you can use a mixture of 1 teaspoon baking soda with a few drops of light horticultural oil in 1 quart water and spray every 7 to 10 days during the spring.

Prune your roses throughout the growing season, too. Deadheading, or cutting off spent flowers, encourages plants to re-bloom. Mulch around your roses to conserve water and encourage soil microorganisms.

Don’t worry whether you’re pruning job is perfect. Roses are super forgiving and you can always trim them up again later.

November Tasks in the Santa Cruz Mountain Garden

Outside my window, the Forest Pansy redbud has started to display its spectacular orange fall color. There’s a suet feeder hanging from the branches so I get to enjoy the antics of the Pygmy Nuthatches, Purple Finches and the Chestnut-backed Chickadees all day long as I watch the changing colors of the foliage. Other than watch the birds and the changing foliage colors what should I be doing out there in the garden?

hedge_parsley_weed
Hedge parsley aka Torilis arvensis

Light weeding is easy now that the soil is soft and moist. The dreaded hedge parsley has germinated early with our October rains. With it’s spiny-ball seeds that stick to your dog’s fur and your socks it is not welcome on my property.  It’s invasive and a native of Europe. They’ll be easy to pull now.

Maybe I will plant a few more bulbs. The ground is cooling and there’s still plenty of time for them to receive adequate winter chilling. Come spring I’ll be happy I did.

california_poppies
California poppies

I just planted wildflower seeds on my hillside. I hoping for more California poppies. I see some of last year’s wildflowers have reseeded. Nature knows when the time is right. I spread the new seeds in swaths and worked them very lightly into the soil, first hoeing off some early weeds that would compete with them.

What not to do in the garden now? I don’t need to prune trees and shrubs at this time of year. Other than clipping a few well placed branches to use for holiday decorations, I’m off the hook for this task. Deciduous trees are still in the process of losing their leaves and are not fully dormant. Evergreen shrubs and conifers can be trimmed lightly but most shaping is done when they start growing in late winter or very early spring. Fall is not a good time to prune. Wounds heal slowly, leaving them more susceptible to disease. As a general rule, don’t prune when leaves are falling or forming. To avoid sap flow on birches and maples prune after leaves mature next year.

hakonechloa_winter
Japanese Forest grass in winter

The growing season is pretty much over for me except to enjoy what’s left of fall color and the ornamental grasses waving their seed heads in the wind. A lot of perennials are dying back but I’m not in a hurry to neaten things up. The seed heads left in the garden supply food for birds and other creatures while the foliage provides shelter for the plant in the cold and frost. Remove anything that has turned slimy or just plain unattractive but leave berries and seed heads for food and winter interest.

At this time of year my garden is visited also by Lesser goldfinches and warblers who will spend the winter and I’m doing them a big favor by not cutting back brown foliage containing nutrient-rich seed heads. Some of the reliable seed producers that I won’t have to clean up this weekend include artemisia, aster, coreopsis, penstemon, sedum, lupine, salvia, black-eye Susan, coneflower, phlomis, monarda, agapanthus and grasses.

Used to be the first frost in our area came about the first or second week of November but not anymore. Be prepared whenever it comes by moving frost tender plants under overhangs if possible or having frost blankets ready to cover frost tender plants.

Pruning Ornamental Grasses

Who doesn’t love a garden filled with the movement and beauty of ornamental grasses especially during the fall? But how do you take care of them after the show is over for the season?

lomandra
Lomandra and NZ flax in mixed planting

When I recently received an email asking what to do with an ornamental grass that had already turned that soft tawny color I figured it was time to brush up on how to care for them. To prune or not to prune? That is the question.

Grasses are distinguished from other plant families by their growth habit. They grow upward from the base of a leaf or shoot and can regrow from the crown when cut back. True grasses generally have extensive root systems which help control erosion. There are other grass-like plants like chondropetalum, New Zealand flax, kangaroo paw and lomandra that resemble grasses in their growth habits and are often some of the best companions for interplanting with grasses.

Most grasses require little care, minimal fertilizer and only occasional grooming. Some flourish with just enough water to meet their needs while others need regular irrigation. Diseases and insect pests are rare and they are not attractive to deer. They have succeeded because of their adaptability and have evolved to suit almost every environment and climate on earth.

japanese_blood_grass
Japanese Blood grass – small and goes dormant

Basically, grasses and grass-like plants fall into 4 different pruning types: Large or small types that go dormant and large or small types that stay evergreen.

Large grasses that go dormant such as miscanthus and calamagrostis are pruned yearly in late fall to late winter. It’s best to hold off on pruning as long as possible to preserve the winter interest and to provide food for birds. When they turn brown and start shedding it’s time to prune. Gather the blades together with a bungee cord or rope and cut down to 10 inches.

Small grasses that go dormant such as Japanese blood grass or fountain grass should be pruned yearly at the same time. Don’t cut them too close to the crown or you risk losing a few clumps. Cut those under 3 feet tall down to 3 inches and those that grow taller down to 6 inches.

guardsman_flax
The Guardsman- NZ flax large & stays evergreen

Large, evergreen grass-like flax and cordyline can be pruned anytime to cleanup and resize but rejuvenation should be done mid-spring. When pruning to freshen up the foliage, select the most damaged leaves and cut them out at the base. If your plant is overgrown or suffered winter damage, prune severely in mid-spring cutting off all the foliage at the base. Tall cordyline varieties can be cut off a few feet from the ground and they will re-sprout below the cut or from the base.

Lastly, small evergreen grasses like carex, acorus, blue oat grass and blue fescue grass can be cleaned up in spring by putting on rubber gloves and combing through the grass. If this kind of cleanup isn’t enough you can reduce the height by two-thirds and in a couple of months they will look good again.

Fruit Tree Care – Fertilization & Summer Pruning

Whether you grow one fruit tree or a home orchard full of them there is always something to learn from an expert and Orin Martin of UCSC Farm and the Alan Chadwick Garden is just the guy to help. With nearly 40 years of hands-on experience at UCSC he says he’s come up with a successful method of caring for fruit trees including pruning and fertilizing . “I’ve made every mistake in the book”, he laughs.

Orin_Martin_prunig_fruit_trees
Orin Martin explaining summer pruning

The UCSC Farm and Alan Chadwick Garden on the campus are both internationally known for training, research and public education. Recently I had the opportunity to join Orin during the Summer Orchard Walk at The Farm as he discussed the care of fruit trees and summer pruning to improve tree shape and productivity. Between jokes he shared many tips including the importance of fertilization and preparing an orchard for fall and winter.

Deciduous fruit trees are genetically programmed to start root growth early as they originated in the cold winter climates of Northern Iran, Uzbekistan and other central Asian areas. Their growing season begins in January or February which is 3-5 weeks prior to any visible bud swell when soil temperatures are still in the low 40’s. With this in mind Orin recommends starting fertilization early. Organic fertilizers take longer to become available to the tree and you want to maximize the early growth spurt in spring.

sunflower pollinator attractors
Sunflowers attract pollinators to garden

Orin has a recipe for fertilizing young fruit trees that is used throughout the Farm and Garden. It’s comprised of compost and an organic source of nitrogen such as blood meal, 8% Nitrogen Sustane or Dr. Earth granular. A young tree will need additional nutrients in May and possibly July if the tree is not putting out sufficient structural growth. Fast acting liquid fertilizer such as fish emulsion and liquid kelp can be substituted for the early summer feeding. The second wave of growth occurs in fall. Slow acting organic fertilizer is best at this time.

Next year’s fruit buds are formed in late spring to early summer at the same time current fruit is growing so nutrient needs are extremely important at this time. If a mature tree is growing well its yearly fertility needs may be met by growing a bell bean crop as green manure over the winter.

Ginger_Gold_apples
Ginger Gold apples with resident cats

The two resident garden cats followed our group as Orin demonstrated summer pruning of Ginger Gold apples, Flavor King pluot and Seckel pears. Most are trained to a open center with some having a modified central leader. I asked what he would do if no central leader grew after heading back a young tree whip. “Then I’d train it with an open center. You’ve got to play the hand your dealt”, he laughed.

“Ladderless” harvesting and care is the goal to pruning in summer and winter. Summer pruning from early August to mid September stops growth and is done to limit height and length of branches to encourage more fruiting shoots. Winter pruning creates the tree’s structure. “When you don’t want a tree any taller, stop winter pruning”, Orin told us.

UCSC Farm_Garden_crops
UCSC Farm crops

Throughout the orchard walk Orin Martin shared interesting tidbits of information. Seems that pest problems such as European blister mite and pear slugs are being observed here at for the very first time.

The USCS Farm & Garden has free monthly guided tours as well as a calendar of educational talks and events. It is open daily for everyone to learn and enjoy. Kids tours are offered during the school year in the Life Lab Garden Classroom.