Category Archives: plant diseases

Methods for controlling plan diseases

bouquets, color in the garden, cut flowers, flowers, mulching, organic gardening, perennials, plant diseases, pruning roses, roses

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.

dogwoods, Flowering trees, plant diseases, planting tips, trees

The Best Dogwoods & How to Grow Them

Alluvial_Terrace_wholesale_nursery
Alluvial Terrace Nursery

There?s nothing like learning about trees from someone who has discovered for themselves what makes a winner and how to grow it. Recently I had the opportunity to tour a small wholesale nursery near Corralitos. Jon Craig has evolved from Silicon engineer to a propagator of plants and trees and he?s all the happier for it. He laughs when he says he has loved plants for a very long time starting with his first job mowing lawns. As a former engineer it?s all about the research and the plants he grows showcase his success.

His very favorite tree is the dogwood. Not just any dogwood but the ones that bloom with the largest flowers for the longest time. There are four main species of dogwood trees. From the Himalayas in China comes cornus capitata, Korea is home to cornus kousa. Cornus florida grows on the east coast and the west coast is home to cornus nuttallii or Western dogwood.

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Jon Craig with cornus capitata ‘Mountain Moon’

We are all familiar with the Eastern dogwood that blooms early in the spring. It?s beautiful but rain and wind can cut short the flowering season many a year and the root system is prone to disease. Our Western dogwood is prone to leaf spot fungal diseases. The Kousa dogwood is a more drought tolerant, disease resistant and a tougher plant all around. Large, showy flowers open after the tree has leafed out and remain for a long time. This makes it good for hybridizing with other varieties.

The Stella series is a mix of a florida on kousa dogwood roots. Vesuvius series is a cross of our native nuttallii with a florida as is Eddie?s White Wonder. There is also a nuttullii-kousa cross called Venus that displays huge flowers and gets its disease resistance from the kousa roots. All these cultivars strive to produce a tree with superior disease resistance and huge, long lasting blooms.

cornus_capitata_Mountain_Moon_closeup
Mountain Moon

Deciduous dogwoods don?t like wet feet especially in the winter. That?s how they develop fungal disease. But there?s an evergreen dogwood that can handle moisture all year round. That tree is Jon Craig?s very favorite. With a name like Mountain Moon you can just picture it blooming high in the Himalayas. Huge flowers up to 6? wide can last from late spring into early summer. After flowering, the fruits begin to form and grow into red balls about the size of large strawberries. This is the reason is it also known as the Himalayan Strawberry Tree. They are edible but bland and tasteless to us. The birds love then though and they remain on the tree while woodpeckers and robins have a feast.

Cornus capitata ‘Mountain Moon’ is a tough tree that can handle strong winds and isn?t bothered by any pests or diseases. They enjoy lots of organic matter as do all dogwoods. Many people think of dogwoods as an understory tree but this location is often too shady. Grow them in a full or partial sun location that gets afternoon shade after 4pm. Add a couple of extra drip emitters or inline drip tubing to your irrigation system and they?re happy.

cercis_Ruby_Falls.1600
Ruby Fall redbud

Besides enjoying the hundreds of blooming dogwoods, I learned about a redbud that is not as fussy as the lovely Forest Pansy. Ruby Falls and Merlot promise to be more reliable in the garden and more heat resistant.

Jon will try his hand growing just about any plant that he thinks others will also enjoy. A fine crop of Alice oakleaf hydrangea grew near a block of Michelia ‘Inspiration’ getting ready to flower and scent the air. The lilacs had finished blooming but the peonies were just starting their show. Jon shared a tip about tree peonies he learned recently from a well-seasoned Japanese gardener. He followed her advice and cut back the tree peony stem in the dormant season forcing it to produce new stems. Voila- they are now loaded with flowers.

peony
peony

Jon grows many other types of dogwood and also Copper beech, magnolia macrophylla, Royal Raindrops crabapple , Sheri?s Cloud nyssa and even a Purple-leaved hazel. I could only fit a couple of 5 gallon cans in my car so a beautiful smoke bush in full bloom and a Black Lace elderberry now call Bonny Doon home. But I have my eye on one of those spectacular Mountain Moon evergreen dogwoods for the back garden.

February gardening tips, plant care, plant diseases, pruning tips, roses

Pruning Roses for Bloom & Vigor

rose_pink_cabbageIn the spirit of practicing what I preach I set out to do a little pruning around the ?ol homestead last week. Since I cut back the hydrangeas pretty hard last year this time round I did only a bit of shaping. The fuchsias haven?t gone totally dormant this year but as they bloom on new wood I cut them back by a third. Then I looked at the roses. I have a few climbers and several shrub roses. This is how I?m going to get the best rose show ever this year.

I want my roses to produce lots of roses on a compact shrub and not just a few OLYMPUS DIGITAL CAMERAexhibition size blooms so I prune my shrubs moderately. My goal is to keep the center of the plant open for good air circulation aiming for a vase-shaped bush with an open center. I?ll cut out canes that cross, saving the better of the two, prune spindly and diseased stems and dead wood. I?ll also prune canes that appear weak or broken. Healthy canes appear green or reddish while old and dying canes are brown. Cut back the remaining stems by about third. When pruning, cut canes at a 45-degree angle just above an outward facing leaf bud or a swelling on the cane. Slant the cut away from the bud to encourage growth outward. Clean pruners after every use to prevent the spread of disease and keep your pruners sharp to make clean cuts.

rose_Hot_Cocoa.2048Heirlooms roses such as David Austin and other old antique garden roses require less pruning 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 cause the cane to flower along its complete length for a beautiful spring display.

My roses still have many of last years? leaves and are pushing new growth rose_Icebergalready. I know those old leaves will spread fungus spores and possibly infect the new growth so I?ll patiently pluck them off. If you have a huge climber this might not be possible and spraying with fungicide may be your only option if you?ve had disease problems in the past. Rake up the debris beneath the plant and discard to eliminate overwintering fungus spores. It’s a good idea to spray the bare plant, coating the trunk, branches and twigs and the surrounding soil with a combination organic horticultural oil to smother overwintering insect eggs and a dormant spray like lime-sulfur or copper soap to kill fungus spores. 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.

Pruning intimidates some gardeners but when you understand the reasons for making the cuts, pruning becomes less daunting. The reasons to prune are for health, appearance and to control size.

Prune your roses throughout the growing season, too. Deadheading, or cutting off spent flowers, encourages plants to rebloom. Every time you cut a rose bloom to bring it indoors or deadhead a fading rose, prune the stem down to shape the plant at the same time. Prune to a spot that has at least 5 leaflets. Roses grow from the point where they are cut, so consider the overall shape of the plant as you snip.

Don’t worry whether you’re pruning job is perfect. Roses are super forgiving and you can always trim them up again later. Roses are like redwoods -you can’t kill one- they’re the energizer bunnies of the plant world.