Hydrangeas: Classic Garden Plants

Is there anyone who does not like hydrangeas?
These perennials have probably the largest sphere-shaped flower clusters in the botanical world. The blooming globes are up to half a foot in diameter, are white, pink, or blue in color and can last for several months, if not longer, whether on the plant or in a vase.
It is for good reason a popular name for the hydrangea is “hortensia,” which means “of the garden,” since hydrangea is the classic garden ornamental. The word “garden” itself is derived from the German word “gart,” which means enclosure. The hydrangea absolutely needs protection from hot sun and wind if it is to grow well, and does even better when it is enclosed on at least two sides by walls, fences or other plants.
What also makes the hydrangea a classic garden specimen, in my opinion, is that some people find it painlessly simple to grow, while others, no matter how hard they try, experience nothing but frustration with this plant.
I have a friend in Encino who has a recessed entryway facing north that is filled each spring with fabulously blooming hydrangeas. The plants are taller than 6 feet and receive a minimum of care, being watered no more than twice a week in very hot weather and with little, if any, fertilization.
As with the vast majority of plants, success with hydrangeas begins with the soil in which they grow. Hydrangeas crave a fast-draining soil. Sandy loam, which contains mostly sand, is ideal. If you have a heavier clay soil, amend it with organic materials. A product called Amend, available in almost every nursery and garden center, consists of compost mixed with rice hulls and does an excellent job of softening up clay soil. Clay particles are microscopic in size and hold water tenaciously. Rice hulls, gigantic by comparison and persisting in the soil for up to 10 years, encourage water to drain around them and down through the soil profile.
I have met people over the years who tell me they grow magnificent leafy hydrangeas but see few if any flowers. When hydrangeas are healthy but flowerless, they are not being properly pruned. The most commonly grown hydrangea, the one you buy or receive as a last-minute supermarket gift, is the bigleaf hydrangea (Hydrangea macrophylla; macrobig, hyllaleaf), also called hortensia or mophead hydrangea. This ubiquitous hydrangea produces the current year’s flowers on the previous year’s growth.
In other words, the buds that are blooming on a bigleaf hydrangea in June 2000 developed during the late summer and early fall of 1999. If you indiscriminately pruned all your perennials last fall or winter, you inadvertently pruned off most, if not all, of your hydrangea flower buds in the process.
Bigleaf hydrangeas must be pruned by the end of July to ensure heavy bloom the following spring. If you prune in fall, winter, or early spring, you will be disappointed by sparse flower production. If you are in doubt about pruning your hydrangea, do not prune it at all. Remember: hydrangeas can grow up to 12 feet tall so do not be afraid to let them find their own way in the world.
Hydrangeas that bloom on last year’s growth and require pruning like the bigleaf hydrangea include lacecap hydrangeas and oakleaf hydrangeas (Hydrangea quercifolia). It is a pity the oakleaf hydrangea, long seen in mail-order nursery catalogs, is not typically available in our local nurseries. In more severe climates such as the Antelope Valley, where more common hydrangeas usually do not grow well, the oakleaf hydrangea would feel very much at home.
Bigleaf hydrangeas bloom in pink or blue, depending on the pH of the soil. Alkaline soil – which is found throughout the Valley – produces pink flowers, while acidic soil makes flowers blue. Aluminum sulfate, applied in the fall, will help to acidify the soil. Still, some experts claim that soil with no aluminum in it, even when acidified with aluminum sulfate, will continue to produce pink, and never blue, hydrangeas. In any case, you will need at least two years of aluminum sulfate application before your hydrangeas turn blue.
To preserve hydrangea flowers, cut them from the plant just as they start to age. Remove all leaves and place stems in a large vase filled with water. Keep stems in water until the flowers have dried completely, which could take up to three months.
< In response to my disparaging remarks about Heliotrope ``Black Beauty'' - that it looks great at the nursery but invariably founders in the garden - I received the following e-mail message from Deb Hodgson of Agoura Hills: ``My heliotrope gets full sun on my patio. It is in a 24-inch container along with rosemary, verbena and a rose bush. It seems to love the full sun. I tried growing it in partial shade before and it didn't do nearly as well.'' GARDEN WONDERS Gardener: Florence Butterworth Residence: Van Nuys Plant of interest: Santa Rosa plum What makes this plant amazing: After half of the tree died, peaches started sprouting from the lower six inches of the tree, at the trunk. According to Butterworth, she never planted a peach tree anywhere near the plum tree. ``I wonder if maybe I got a grafted plant and didn't know it,'' she says. Maintenance: ``I just water it, and when the fruit comes on, I let people pick them so the birds and squirrels don't get to it first.'' What Joshua Siskin says: ``Plums are grafted onto peach root as friends stalks to give the plant durability and vigor. The peaches growing from the tree are probably bland, if not bitter. If you can get 20 productive years from a plum tree, you've done quite well. After that, the plant starts to decline. You get less and less fruit, and you might get stalks from the peach plant where the graft occurred.'' - Mike Chmielecki

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