Plants can adapt, to a point.
COLUMN: ROOTS OF WISDOM
Would you be surprised to learn that plants can suffer from exposure to excessive sun just as people can? Are you also aware that plants differ in their susceptibility to the sun's rays?
Regretfully, both statements are true. Plants construct themselves according to their genetic blueprints and to changes in their environment.
Last summer our plants were exposed to one set of conditions. This year the weather conditions are almost the exact opposite.
As to the genetic predispositions of plants, most gardeners would have no difficulty realizing that many plants prosper in semi-shade to deep shade.
Many ferns, hostas with a high ratio of white to green in their leaves, fuchsias, lobelias and dozens of other plants perform best with less than six hours of sun a day.
Other plants, such as geraniums, salvia, zinnias, tomatoes, peppers and peonies, are happy when placed in full sun. Naturally trees, shrubs and hedges are considered full sun plants.
Homeowners have noticed that after a winter spent indoors the majority of their houseplants must acclimate to higher light levels when placed outside. The plants' leaves have been modified by the low levels of indoor light and need time to reconfigure to bright light conditions.
Sun plants and shade plants both need a week or two to build thicker palisade tissue to filter light energy so that interior tissue is protected.
Some plants are constructed to cope with extreme light levels. Think cacti and succulents.
In some instances they have shed their leaves and function solely on the sunlight reaching their stems. Most of them have constructed a thick skin (a cutin layer) to protect water loss. Others arm themselves with thorns as protection from browsing animals.
Other coping mechanisms exist, but you get the idea.
Plants that normally grow in the shade of the forest floor produce thin broad leaves to capture the filtered sunlight that reaches them. Their palisade layer is thin to allow all available sunlight to penetrate the leaf.
Thus, plants are constructed to cope with the environmental conditions of their native land. They further are able to modify their blueprints, within limits, to adjust to current conditions.
What happened last year? Extended periods of no sun, extreme moisture and cool temperatures barely met growing conditions for either sun or shade plants. Disease attacks were common; production was poor.
Fast forward to this year: Record- breaking heat; weeks without meaningful rain, and a searing sun that provides no relief.
Immediate results of this stressful environment include leaves smaller than usual, brown margins on leaves, fruit developing with white patches indicating sunburn of interior tissue. Called sunscald, cellular damage has occurred.
Do not prune, spray or fertilize until weather conditions moderate considerably.
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|Publication:||Telegram & Gazette (Worcester, MA)|
|Date:||Jul 25, 2010|
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