Rescue My Garden: Rain, Water, and the Drought
Water is a good servant, but it is a cruel master.
-- John Bullein, 1562
Rainfall: One event Does Not a Seasons Rainfall Make
Q: It has rained pretty hard the last two days. Will that make up for the drought that has devastated out landscape for the past many weeks?
A: The rain will take some of the edge off of the drought, for a little while, but we may easily be back to that edge within 4 or 5 days without more iterations of rainfall. As far as trees and shrubs are concerned, the damage is already done. I’ve already seen dying river birches and dogwoods, and damaged maples. Some trees are already showing early fall color as they prepare to give up and wait for next year.
But many signs won’t show up until next spring or even the next couple of years. Drought-stressed trees and shrubs may become more susceptible to disease and insects. Some maples’ crowns may not seem as full as they were before the drought.
Watering trees slowly and deeply during dry summers can be boring, but it’s the best way to save the most valuable components of your landscape. During a hot summer, newly planted trees should get thoroughly watered every four to five days (allow 20 gallons for a 6- to 8-foot tree).
Counting the Drops
Q: After a month of drought we had two quite heavy rainstorms. But when I went out to work in my vegetable garden the soil was dry just a couple of inches down. I know it didn’t run off, so what happened to the water?
A: The rainstorms may have been quite heavy, but they weren’t also quite long, and therefore they probably didn’t deliver as much water as you thought they did.
The soil has already told you all you need to know: however much it was, it wasn’t enough. As I wrote last week, you need to get information about your soil from your soil. Make it a regular habit to investigate your soil in terms of moisture. Stick your trowel in the soil and have a look. If it’s wet eight inches down, you’ve watered enough.
Dealing with the Deadly Drought
Q: This summer’s drought is hurting my annuals and vegetables. Perennials look O.K. but not great. My water supply is limited so I can’t water everything. I have put on lots of mulch. Is there anything else I can do?
A: Consider the long term and give that rationed water to the most important plants – a form of triage. Annual flowers and vegetables will be history by winter, no matter what, while the expensive and slow-growing items like Japanese Maples should be given scarce resources.
I understand the desire to try and rescue the neediest; plants with hanging heads are heart-wrenching, but plants already stunted by drought are the least likely to thrive later, even if they do survive. It’s best to water things that are O.K. but just a little peaked. And don’t forget that spring-flowering shrubs like lilacs start building next year’s blossoms as soon as they finish this year’s show and they need water to do it.
If possible, water whole areas rather than single plants. Dry soil wicks moisture away, so spots watered in isolation are surrounded by desert-like soil. If you’re determined to save annual flowers, shear them back. If rain comes, they will rapidly put on new growth and a burst of bloom.
