Help plants tolerate hot, dry conditions
Short-funded pensions and long-winded politics aside, we can't guarantee a lot in Illinois. Nonetheless, if the season says summer, then the thermometer says sizzling. To compound our garden troubles, Illinois' high summer heat is often escorted by low summer rainfall. In a gardener's work day, we drip more than the clouds.
I always chuckle a bit when I read authors' lamentations about the extreme gardening of New England or the challenges of a southern U.S. garden. Granted, I'm sure they have their trials. But here in Illinois, we are extreme — times two. Our tenacity as gardeners and the resilience of our plants are tested at both ends of the temperature spectrum. We have cold winters and hot summers. Our perennial plants have to be bipolar as they must tolerate (hopefully thrive on) both tips of the thermometer.
The good news is plants are amazingly adaptive to weather extremes. Our challenge is in how we can help them thrive. We can modify environmental conditions, do our homework to select the right plants for the specific area and be willing to learn from our mistakes along the way.
In summer, we may ponder those sunny, dry places and their accompanying suffering plants and wonder how can we help beyond a sun umbrella and a water sprinkler. Shade structures are not just for our patios.
At the Idea Garden at the University of Illinois Arboretum, Master Gardeners devised a shade structure fit for understory plants that would have been shaded by trees in their native areas. Imagine a 3-foot tunnel made of brown-painted PVC pipe and rattan fencing. The shade-loving caladiums are happily tucked into their shady cave. The shade of large leaved plants such as elephant ears, bananas or large shrubs may be just enough for smaller shade-loving plants to thrive. Shade isn't just what we can fit under.
When we add organic matter such as compost to our soils and top our garden beds with wood chip mulch, we also are helping plants tolerate hot, dry conditions. Organic matter in and on soils helps to retain moisture and lower soil temperatures. Organic matter and mulches are good for many plants, but be aware, organic matter is not the answer to all garden grief. We have to go back to their roots.
Plant selection is a joy or a burden depending on how fanatical you are about gardening. I love researching plants and finding new ones to try. If you really want to know a plant, research where it is native and what environmental conditions are there.
For example, English lavender is a favorite plant among plant lovers and fragrance lovers. It also is commonly killed by well-meaning gardeners. They see bountiful lavender in other people's gardens. So what are they doing wrong?
First, several different lavenders are available and not all are winter-hardy here. English lavender (Lavandula angustifolia) is winter-hardy. As a native to rocky coastal areas of the Mediterranean, it requires well-drained soil. Lavender grows best in dry sandy or rocky soils in full sun. Lots of organic matter is a killer to lavender. Fertilizer, organic mulch and compost can easily produce a rotted lavender plant. The best mulch for lavender is sand, pea gravel, crushed rock or poultry grit, not wood chips.
Next week, I will discuss more of these quirky plants for hot, dry areas.
A free distance learning telenet, Winter Wise Your Landscape: Knowledge to Prevent Costly Mistakes, will be held at 1 p.m. Tuesday. The program will be held at UI Extension offices. Get more bloom for your buck and find balance in both your landscape and pocketbook. To register, call the Champaign office at 333-7672, the Danville office at 442-8615, the Onarga location at 815-268-4051 or visit http://web.extension.illinois.edu/cfiv/.
Sandra Mason is unit educator, horticulture and environment, for the UI Extension, Champaign County. Contact her with questions or comments at 801 N. Country Fair Drive, Champaign, IL 61821, call 333-7672, email firstname.lastname@example.org or fax 333-7683.