Inpreparing for a consultation for another site under native oak trees at risk for SOD I found the latest host list published by the Sudden Oak DeathTask Force . The new list updated March 2008 also lists plants naturally infected and lots of information re. spreading the fungus as well as tips on sanitation. The latest information on prevention and keeping the immune system of your trees up if also available. I did find that a few of the plants that I was going to recommend for homeowners with oaks on their property have now been listed as vectors. They are coffeeberry, toyon, berberis aquifolium, manzanita and some varieties of ceanothus. This is important information for all of us to know.
The end of daylight savings time signals to me that autumn is really here in our mild California surroundings. Enjoy these crisp mornings and warm days and to make your garden more compelling, try mixing in late flowering perennials as well as trees and shrubs with bold leaves and a wide range of autumn color.
Bright trees and shrubs add color flashes to fall gardens. Sasanqua camellias have already started blooming and will continue to flower throughout the winter. In addition to asters and rudbeckia, Japanese anemones are the stars of the border at this time of year. The electric blue flowers of dwarf plumbago contrast with reddish leaves as night temperatures dip, Encore azalea and Endless Summer hydrangea are blooming now, too.
Other perennials that are blooming now are California fuchsia, Pineapple sage and Mexican bush sage.
I love my patch of California fuchsia. Starting in the summer and flowering through fall this California native is covered with orange or scarlet-orange flowers that attract hummingbirds like crazy. A great plant along the path or draping over a rock wall this perennial thrives in areas that might fry other plants. Also known as Epilobium canan or Zauschneria it is in the evening primrose family and native to dry slopes and chaparral especially in California.
Mexican bush sage look great blooming alongside California fuchsia. Orange and blue are opposite on the color wheel so they look fabulous together. The bright red flower spikes of Pineapple sage look pretty nearby so the whole area is a hummingbird feast.
But what about vivid foliage in the garden? Which plants put on the best show in our area? Here are some of my favorites.
A great tree for the gardener interested in edibles is the Fuyu persimmon. This beautiful small tree is ornamental with glossy green leaves and also offers a dramatic fall display in shades of yellow, orange and red. Bright orange fruit begins to develop in late October and clings to bare branches usually through December. The tree looks more like it’s covered with holiday ornaments than fruit. And have you priced persimmons in the store lately?
Blueberries are a must for the edible gardener. They make a beautiful hedge that provides showy red or yellow fall color. Because of our colder winters here in the mountains, we can grow both northern highbush which are self-fertile and southern highbush which produce better with another type to pollinize them. They can be great foundation plants around the home as well as in the garden.
A vine that lights up with the onset of autumn is Rogers Red California grape. If you have an arbor, wall or fence that need covering quickly, this is your plant. The green and gray leaves are transformed in autumn into great draperies of rich, scarlet red leaves with clusters of summer fruit turning all shades of purple.
Japanese barberries are deer resistant, low water-use small shrubs that make them superb hedge plants, background plants against fences and foundations or accent plants. Red or lime colored summer foliage changes to orange, red or amber in the fall. I love the graceful growing habit of many of the varieties but there are pillar forms and also dwarf types.
Bright foliage on trees like red maples, liquidamber, Chinese pistache, ginkgo, ornamental pear, cherry or crabapple, dogwood, goldenrain, locust, katsura, oak, redbud, sumac and witchhazel all add to the fall drama of the landscape.
Light up your garden as the light fades and the days shorten. I know my garden needs a greater variety of fall color than just the Japanese maples in pots on the deck and the barberries. I’m waiting for my purple smoke bush to turn luminous scarlet and add color flashes to my fall garden.
I feel sorry for them. They are the wallflowers of the nursery. Shoppers barely glancing their way before moving on to attention getters like dinner-plate dahlias. In the garden, though, they shine. They are the work horses of the perennial border. I’m talking about true geraniums- those hardy, versatile, long blooming plants for edgings, borders and ground covers.
Most people use the common name geranium to describe what is actually a pelargonium. Ivy geraniums, Martha Washington pelargoniums and zonal geraniums are all pelargoniums. Hardy geraniums, also called cranesbill, look very different. Leaves are roundish or kidney-shaped and usually lobed or deeply cut. Flower colors include beautiful blue, purple, magenta, pink or white and often completely cover the plant with color. I’ll bet if you visited a garden on a tour or admired a picture in a garden magazine it contained true geraniums. Here are just a few strong performers available among the dozens of species.
Geranium maderense grows best in shade. This dramatic native of Madeira is the largest geranium with huge 1-2 foot long leaves shaped like giant snowflakes. Clusters of thousands of rose tinted flowers form on a 3 foot trunk. This perennial is short-lived but self sows freely. Add some of these architectural plants to your border for color and structure.
Blue flowers in the garden are always a hit as they combine so well with other colors. Geranium Orion’s abundant clear blue flower clusters bloom over a long season. Use this 2 foot spreading plant in sun or part shade in a mixed border or as a groundcover. There are other blue flowering geraniums. I grow geranium ‘Brookside’ on my own garden. It’s on it’s second round of blooms. It’s large bright blue flowers are larger than ‘Johnson’s Blue’. ‘Rozanne’ is another common favorite with stunning blue flowers.
Another fast growing variety is geranium incanum which covers itself spring through fall with rosy violet flowers. Cut back every 2-3 years to keep neat. This variety endures heat and drought better than other types but needs some summer water. It self seed profusely which might be exactly what you want as a groundcover in a problem area.
If pale pink is your color, plant geranium x cantabrigiense ’Biokova’. This excellent groundcover spreads slowly. The numerous one inch flowers are long lasting and cover the plant from late spring to early summer. Their soft pink color is indispensable when tying together stronger colors in the border and the lacy foliage is slightly scented.
Another geranium in the same family is ‘Karmina’. I’ve been growing this dark pink flowering variety for several years. With lush green leaves on a low spreading plant it’s pretty even when not in bloom.
There are a couple other varieties that are popular and deserve a try. They are Award Winning Mavis Simpson’ and Russell Pritchard’. Both have bright pink or purple flowers and make good additions to your perennials.
Water is our most precious resource. One of the Apollo 11 astronauts recently said that the look back from the moon at our planet and blue oceans to be even more impressive than the moon itself. Life can’t exist without water. You are the steward of your own piece of planet earth. How you water can make it thrive and you can save water at the same time.
With summer water bills arriving this is a good time to re-visit how often and how much to water that landscape you’ve spent so much money to create. Basically, you’re wasting water if you water too shallow or too often. Here are some guidelines.
Photosynthesis is one of the most remarkable biochemical processes on earth and allows plants to use sunlight to make food from water and carbon dioxide. At temperatures about 104 degrees, however, the enzymes that carry out photosynthesis lose their shape and functionality. A garden that provides optimum light and water but gets too hot will be less vigorous.
Plants have natural systems that respond to heat problems. Plants can cool themselves by pumping water out through the leaves for a kind of swamp cooler effect. They can also make “heat-shock” proteins which reduces problems from over heating. All these strategies can take resources away from a plant’s other needs like growth, flowering and fruiting.
So how much water do different types of plants need during the heat of summer?
Be sure that you water trees and shrubs deeply checking soil moisture first with a trowel. Established small to medium shrubs should be watered when the top 3-6″ is dry, large shrubs and trees when the top 6-12″ is dry.
As a rule of thumb, trees and large shrubs need deep but infrequent watering. They should be on a separate valve than your smaller shrubs and perennials. Water ornamental trees 1-3 times per month depending on the type and soil. Tree roots grow 12-36” deep and require 10 gallons of water per inch of trunk diameter.
Apply water with a soaker hose, drip system emitters or hand held hose with shut off and soft spray attachment according to your water district’s restrictions. Don’t dig holes in the ground in an effort to water deeply. This dries out roots even more. Be sure to water the root zone to the indicated root depth every time you water. Watering deeper than the root zone only means you are wasting water. You can test how deep you watered by pushing a thin, smooth rod into the ground soon after you irrigate. The soil probe should easily slide through the wet soil but become difficult to push when reaching dry soil.
The roots of smaller shrubs are 12-24” deep in the soil. Established native shrubs may need only monthly waterings to keep them looking their best while other shrubs may need watering every 7-10 days during the heat of the summer. Perennial roots only go down 12” or so and may need watering once or twice a week depending on type.
When is the best time to water? Watering in the morning is the most efficient whether you water by sprinkler, drip system, soaker hose or by hand. The water soaks deep in the soil without risk of evaporation. It bolsters the plant for the day and has dried from leaves by evening reducing the risk for foliar diseases like mildew. Plant roots are also more receptive to watering in the morning.
Is it true that water droplets will scorch leaves in the midday sun? According to a study, fuzzy-leaved plants hold water droplets above the leaf surface and act as a magnifying glass to the light beaming through them so there is a very slight chance of scorch. The study also reported that water droplets on smooth leaves, such as maples, cannot cause leaf burn, regardless of the time of day.
I’m waiting patiently for the buds on my pink flowering currant to start lengthening a bit more. I wasn’t counting on the recent snow and cold snap but the buds are showing color and are doing fine. Although still small at this stage I’ve assured my hummingbird population that they’re on their way. When I was out pruning last week I didn’t touch this plant otherwise I’d have cut off all those potential flower clusters loaded with nectar. This is what I did do in my garden.
To stimulate new growth I trimmed woody evergreen shrubs like abelia and loropetalum. The Mexican bush sage and artemisia were cut to within a few inches of the ground. I don’t use this approach on lavender or ceanothus, though. Lightly prune those after blooming later in the season and don’t cut back to bare wood inside the plant.
Between rain storms I’ll prune my fuchsias back by a third and remove dead, crossing branches and interior twiggy growth. The hanging fuchsias will be cut back to the pot rim. Fuchsias bloom on new wood so even if your plants didn’t lose all their leaves cut them back.
I cut back all the hydrangeas stems that bloomed last year and will apply a soil acidifier soon as I want the flowers as blue as I can get. Although aluminum sulfate is the traditional favorite for quickly acidifying soil it’s not as kind to beneficial soil microorganisms. Coffee grounds, pine needles, peat moss and cottonseed meal are better for your soil.
Don’t prune spring flowering shrubs like lilac, weigela and spirea or flowering trees such as cherry, plum and crabapple now. These and plants with buds like rhododendron, azalea and camellia should be pruned after they flower. You can cut some branches while they are blooming to bring into the house for bouquets.
Even if you have already pruned your roses be sure to remove old leaves still clinging to the plant. Those will most likely develop fungal spots and diseases later if you don’t. Rake up any debris beneath the plant and discard to eliminate overwintering fungus spores
Roses are super forgiving and you can trim them up again using the following guidelines. The goal is to produce lots of roses not just a few of exhibition size. Aim for a vase-shaped bush with an open center.
Prune old garden roses that bloom once in the spring after flowering. Climbing roses require little pruning. 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.
Wait to prune back perennials that may have their new foliage damaged in a late frost. Same goes for shrubs that might have gotten hit by frost. That damaged foliage can protect the plant from further frost damage. Mid-March is the estimated date of hard frost in our area or at least it used to be. We gardeners are always betting Mother Nature will go our way and our efforts will not have gone in vain.
Prune fruit, nut, shade trees and deciduous vines like clematis.
Cut back ornamental grasses if you live where you rarely get frost. I’m pruning California fuchsia, salvia ‘Bee’s Bliss’ and hummingbird sage now. They look okay but I want the encourage new, compact growth.
And now I’m making myself a cup of tea and watching the chipmunk action in my garden. All of nature is getting ready for spring.
Some people wait all year for fall weather to arrive. The heat of summer is over and the tourists are gone along with that pesky fog along the coast. For us up here in the Santa Cruz mountains, this is one of the best times to be outside. Here are tips for early fall in the garden.
Late fall is not a good time for major pruning so if you have some shrubs that need a tune-up do it soon. Wounds heal slowly later in the fall, leaving them more susceptible to disease. As a general rule, don’t prune when leaves are falling or forming. Wait to prune most trees until late in the dormant season or in late spring after leaves and needles form. To avoid sap flow on birches and maples, prune after leaves mature. Fruit tree summer pruning should have already been done when growth ceased.
Refresh perennials, such as butterfly bush, salvia and yarrow by cutting a third to half of their growth later in the fall.
Rake leaves- compost or put in your green can. If large leaves are left in place they will mat down and set up fungal problems come spring.
Remove dead and diseased leaves from under camellias, rhododendrons and roses.
Now through October, divide summer blooming perennials that are overgrown and not flowering well. Alstroemeria, agapanthus, coreopsis, iris, daylily, yarrow, rudbeckia, calla lily, aster and penstemon fall into this category. 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. If you’re on a roll out in the garden, though, go for it now. You never know what other projects you may be working on next spring.
Start perennial flowers seeds now so that they will be mature enough to bloom next year.
Fertilize shrubs lightly one last time with an all-purpose organic fertilizer or layer of compost. Use compost only on California natives.
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. Planting early ensures your plants get a good start before cold weather sets in and growth mostly stops until spring. You’ll be able to start harvesting in just a couple months if you start now that the weather has started to cool.
If you aren’t going to grow vegetables in the garden this fall consider planting a cover crop like bell beans, fava beans and vetch after you’ve harvested your summer vegetables. Next month I’ll talk about how to go about doing this and how this benefits your soil.
Cut back berry vines that have produced fruit. Canes of the current season should be trained in their place.
Spider mites and thrips are especially prolific during the late 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.