Category Archives: perennials

Growing Chrysanthemums

It’s that time of year when every store I visit has mums for sale. Chrysanthemums are so common we often think of them as temporary filler plants in fall containers and borders. But mums are perennials and can play a bigger role in your garden if you let them.

Garden mums

Chrysanthemums were first cultivated in China as far back as the 15th century. Over 500 cultivars had been recored by the year 1630. There are records in Japan from the 8th century relating the mums.

The botanical name for the garden chrysanthemum has been changed to dendranthemum grandiflorum but I never hear anyone use this name. It doesn’t exactly roll off the tongue.

Yellow or white chrysanthemum flowers of the species. C. morifolium are boiled to make tea in some parts of Asia. In Korea, a rice wine is flavored with chrysanthemum flowers. Chrysanthemum leaves are steamed or boiled and used as greens in Chinese cuisine.

Another variety of chrysanthemum- cinerariaefolium- is important as a natural source of insecticide. The pyrethrins extracted attack the nervous system of all insects. it is harmful to fish and should be used with caution but it’s not persistent in the environment and is biogradable.

Mums, black mondo grass, Blue Hokkaido squash

Grown for years to flower only in late summer and fall, chysanthemums are short day plants, setting buds when they receive light for 10 hours and darkness for the other 14 hours of the day. This is why mums bloom in the spring on leggy stems if they are not cut back. And this is how growers manipulate their blooming, adjusting the dark and light periods with shades in the greenhouse so buds will form in any month. They’re nearly constantly available in grocery stores and florists in every season.

At this time of year when garden mums abound pick a plant with lots of buds. They bloom only once and won’t set more flowers until next year. Those buds, though, last a long time if you don’t let them dry out.

The specific type of plant doesn’t matter since they all have long term growth potential. If you particularly like one color or form of chrysanthemum, plant it now to enjoy again next year. You never know what the growers might decide to grow next season.

Choose a well-drained, sunny spot to plant them. Like many members of the aster family, mums don’t tolerate soggy ground. After blooming, trim off the old flowers and cut back plants to within a 4 or 5 inches of the ground. If you started with 4 inch pots, trim back by half.

Next spring pinch them back whenever growth gets to 8 inches tall. Keep pinching until July, then allow plants to start forming buds for the traditional fall show. Mums need regular water so plant them in spots where you have other plants with the same water needs.

All parts of chrysanthemum plants are potentially toxic to dogs, cats, horses and other mammals. Ingesting the plants can cause vomiting, diarrhea, excessive salivating, rashes or lack of coordination, according to the University of California Davis School of Veterinary Medicine.

 

The Early Fall Garden To-Do List

The autumnal equinox happened September 22nd. It’s the official start of fall when the sun crosses the celestial equator and moves southward. The earth’s axis of rotation is perpendicular to the line connecting the centers of the earth and the sun on this day. Many people believe that the earth experiences 12 hours each of day and night on the equinox. However, this is not exactly the case.

During the equinox, the length is nearly equal but not entirely because the day is slightly longer in places that are further away from the equator- like where we live. Also the sun takes longer to rise and set in these locations as it does not set straight down but in a horizontal direction.

Variegated alstroemeria

It was a hot summer and I’m ready for fall. This is the perfect time for transplanting or adding new plants to your garden. Why? Cooler air is kinder to plant foliage while soil temperatures are still warm creating an excellent environment for new root growth. In the fall many plants and trees, even broadleaf evergreens, are entering a period of dormancy. With no need to allocate resources into foliage, plants are transferring all their energy into roots and storing nutrients for the cool months ahead. By spring, the new root systems should be well established.

Now through October, divide summer blooming perennials like alstroemeria, agapanthus, coreopsis, iris, daylily, yarrow, rudbeckia, calla lily, aster and penstemon that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart although they don’t always bloom the first spring afterwards due to the energy they use re-establishing themselves. Start perennial flowers seeds now so that they will be mature enough to bloom next year.

bergenia cordifolia

Fertilize shrubs lightly one last time with an all-purpose organic fertilizer or layer of compost. Use compost only on California natives.

Fertilizing roses now will encourage them to bloom again this fall. To keep roses blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new flower bud to grow much sooner than if you cut to one with only three leaves.

Plant cool season veggie starts like broccoli, cabbage, cauliflower, chard, lettuce, spinach, brussels sprouts, onions and leeks in soil enriched with 4-6″ of compost as summer vegetable crops will have used up much of your soil’s nutrients.You can sow seeds of beets, carrots, radishes, spinach, arugula, mustard and peas directly in the ground.

Cut back berry vines that have produced fruit. Canes of the current season should be trained in their place.

hemerocallis

Spider mites are especially prolific during the summer. If some of the leaves on your plants are pale with stippling, spray the undersides of infected leaves with organics like insecticidal soap switching off with neem oil as they build up a resistance to one of the pesticides. Plan to spray with a horticultural oil in the winter to kill overwintering eggs.

The weather these days is perfect for being outside. Enjoy it and this place we call home.

Tranquil Blue in the Garden

With the heat of summertime upon us I’m drawn to those areas in my garden that have blue, white and lavender flowers. A hot day just seems cooler there.

Washed out magenta is nature’s favorite go-to color and the shade that hybrids will revert to it if allowed to go to seed. Among gardeners, red is a favorite color. Orange and yellow come next, then pink and purple with blue and white both comparatively rare in nature last on the list.

geranium ‘Orion’

So naturally, most of us gardeners want the elusive blue flower in our gardens. Knowing that cool colors recede, place them around the edges or at the back of a garden to make your space appear wider or deeper.

True blue flowers are rare. We use words like cerulean, azure, cobalt, sapphire, turquoise, electric blue or steel blue when describing blue flowers. Hybridizers have tried for years to produce a true blue rose or blue daylily. Blue plant pigment is hard to manipulate. It occurs in the daylily as a sap-soluble pigment and is difficult to segregate. Lilacs, purples, orchids and mauves we have and working with them hybridizers may eventually get near blue, but pure blue probably never. Recently, some companies have found a way to insert some blue in the center of their daylily flowers but a totally blue daylily has never been produced.

Rose hybridizers striving for true blue have come close by

hydrangea macrophylla

crossbreeding lavender hybrid teas in order to produce offspring having optimum amount of cyanidin, the pigment that imparts purple or magenta tones and flavone, the pigment that gives light yellow tones.The results have been more of a silvery lilac or mauve. A blue rose is still in the future although labs in Australia and Japan are genetically modifying the pigments from petunias to produce a blue rose. Their results are not yet perfected and these roses are more of a lilac in color and can not survive conditions outside the lab. It is apparently very difficult to isolate the pigment cyanadin. Delphiniums have a monopoly on it.

omphaloides

The color blue is calming and tranquil. It is the color of serenity and peace and is said to slow down the metabolism and reduce the appetite. When brightened with white or combined with yellow or orange in a complementary color scheme the results of blue in the garden are breathtaking. The great English gardener Gertrude Jekyll used plants with golden leaves or clear yellow flowers to spice up blue gardens. Just remember that blues and purples are the first flowers to fade as darkness falls so be sure to have those whites and yellows to carry your garden into evening.

There are many blue perennials as handsome as they are durable that we can enjoy in our gardens today.
Some of my favorites are old fashioned hydrangeas, violas and campanula. Both are valuable in the shade garden along with omphaloides and brunnera. The blue spikes of a long blooming peach-leaf campanula just go together with the white and green variegated foliage of Jack Frost Siberian bugloss.

agapanthus africanus

In early spring we are dazzled by our native ceanothus which bloom with deep blue, sky blue or electric blue flowers. Emerald Blue phlox subulata carpets the ground in spring with clear blue flowers that top creeping stems. Penstemon Blue Springs, a California native hybrid, carries dense spikes of bright blue, bell-shaped blossoms.

Make sure your garden has a blue section to cool you on a hot day.

Why Prune in the Summertime?

Pruning is a good way to spend a couple of hours in your garden. I’m not talking about trimming plants into little balls but the kind of pruning that makes for a healthier and happier plant.

Sango kaku Japanese maple- summertime

If you grow Japanese maples now is the time to remove dead branches and train your tree to look like one of those specimens you see in the magazines. Thinning cuts build your ideal tree limb structure. If yours is a young tree, though, don’t be tempted to head back long branches too soon. As these mature they give your tree that desirable horizontal branching.

This principle is important to keep in mind when you train any young ornamental tree. Lateral buds grow along the sides of a shoot and give rise to sideways growth that makes a plant bushy.

Summer pruning of fruit trees controls size by removing energy-wasting water sprouts. Summer is also a good time to remove leafy upper branches that excessively shade fruit on the lower branches. Winter pruning is meant to stimulate the tree. Summer pruning uses thinning cuts-where the branch is cut off at its point of attachment instead of part way along the branch- and these cuts do not encourage new growth but control the size of your tree making fruit harvest easier.

Summer pruning also can control pests like coddling moths, mites or aphids. Just be sure to dispose of these trimmings and don’t compost them.

Espalier apple tree

If you have apricots and cherries, summer pruning only is now advised as they are susceptible to a branch killing disease if pruned during rainy weather. Prune stone fruits like peaches and nectarines after harvest by 50%. They grow quite rapidly. Apricots and plums need to have only 20% of their new growth pruned away.

Be sure to thin the fruit on your trees. That’s another good reason to keep them smaller so you can more easily reach the branches. The best time to do this is when the fruit is still small. Thinning fruit discourages early fruit drop and improves the quality of the remaining fruit. It helps to avoid limb damage from a heavy fruit load. Also it stimulates next year’s crop and helps to avoid biennial bearing. Left to their own devices, a fruit tree may bear heavily one year and then light or not at all the next year. Some types of fruit trees like peaches and Golden Delicious apples are likely to bear biennially if the current year’s fruit crop isn’t thinned.

While I have the pruners out I’ll be shearing back early flowering perennials to encourage another round of blooms. And I’ll add some more mulch to areas that are a little thin. I’ll be checking the ties on my trees to make sure they aren’t too tight and remove the stake if the trunk is strong enough to support the tree on its own.

Also I’ll be looking for any pest problems so I can do something about them before they get out of hand. I’m OK with a few holes here and there but a heavy infestation should be trimmed off or sprayed with an organic insecticide. I also inspect the tips of my fuchsias regularly for fuchsia mites and clip off any distorted growth. I hate to spray even organics on them due to the hummingbird activity.

Most importantly, enjoy your time outdoors. If a task is too big to do at one time, break it down into smaller sessions. As they say, take time to smell the 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.

Late Summer Tasks for the Garden

It’s darker in the mornings now with the sunset coming earlier each evening. All that time I thought I’d have back in June to get things accomplished in the garden has vanished in what seems like a wink of an eye. Still the weather these days is perfect for being outside and pecking away at my to do list. There are also some late summer/early fall tasks that need attention.

alstroemeria_variegatedAlstroemeria ‘Rock & Roll’

Now through October, divide summer blooming perennials like alstroemeria, agapanthus, coreopsis, iris, daylily, yarrow, rudbeckia, calla lily, aster and penstemon that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart although they don’t always bloom the first spring afterwards due to the energy they use re-establishing themselves. Start perennial flowers seeds now so that they will be mature enough to bloom next year.

This is the perfect time for transplanting or adding new plants to your garden. Why? Cooler air is kinder to plant foliage and soil temperatures are still warm which creates an excellent environment for new root growth. In the fall many plants and trees, even broadleaf evergreens, are entering a period of dormancy. With no need to allocate resources into foliage, plants are transferring all their energy into roots and storing nutrients for the cool months ahead. By spring, the new roots system should be well established.

Perhaps it’s time to remove or reduce lawn. Replant with more drought tolerant ornamental grasses or perennials.

achillea_pinkAchillea millefolium

Fertilize shrubs lightly one last time with an all-purpose organic fertilizer or layer of compost. This advice doesn’t apply to California natives. They like compost only around the roots during the winter while they get ready for their growing season.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in the fall. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new flower bud to grow much sooner than if you cut to one with only three leaves.

Plant cool season veggie starts like broccoli, cabbage, cauliflower, chard, lettuce, spinach, brussels sprouts, onions and leeks in soil enriched with 4-6″ of compost as summer vegetable crops will have used up much of your soil’s nutrients.You can sow seeds of beets, carrots, radishes, spinach, arugula, mustard and peas directly in the ground.

soil_builder_cover_crop_mix-1600Soil builder cover crop mix

If you aren’t going to grow vegetables in the garden this fall consider planting a cover crop like crimson clover, fava or bell beans after you’ve harvested your summer vegetables.

Cut back berries vines that have produced fruit. Canes of the current season should be trained in their place.

Spider mites are especially prolific during hot, dry weather. Sometimes you don’t even know how bad the infestation is until all your leaves are pale with stippling. Periodically rinse dust and dirt off leaves with water. Spray the undersides of infected leaves with organics like insecticidal soap switching to neem oil if they build up a resistance to one of the pesticides.

And whatever you do, enjoy being outside in this beautiful place we call home.