Garden Doctors: Drought challenges and solutions

Jackie B. writes: I have a couple of questions for you. What can you tell me about the polyacrylamide granules used for retaining moisture in the soil? Are they worthwhile? Secondly, what are some recommended drought tolerant and easy maintenance plants that will attract beneficial insects into the garden?

Polymer (or polyacrylamide) granules do just that; they help retain water in the soil and therefore make it available to the roots as they release moisture for an extended period of time. This is not a new product and the U.S. Forest Service has used it for some time when planting new seedlings. Personally, I have found it to be worthwhile and it has made the difference in helping plants become established when water is not available frequently, or in soils that do not hold water such as sandy or very rocky soil. It is not a fertilizer.

Soil Moist is one product that is available in our local nurseries and garden centers.

It is expensive, but a little used goes a long way. As an example, a plant purchased in a five-gallon container would use 2 tablespoons of polymer granules reconstituted and poured around and below its root ball. I prefer to wet the granules first in order for them to completely absorb water (and it is amazing how much is absorbed). I also make sure the planting hole has some water in it before adding the wet granules. Placing the dry granules in the soil first seems to draw the moisture from the root ball. Over the years experimenting with this product, my method of use seems to me more effective. The directions on the container may be different.

It can be used for containerized plants and they won’t have to be watered on a daily basis. And, it is effective when applied along new vegetable starts in the garden. Its use is certainly worthwhile during drought conditions.

Here are a few suggestions for native plants that have seasonal color appeal in the home garden, are drought tolerant once established, easy to grow and attract beneficial insects.

Seaside daisy, Erigeron glaucus, has colorful daisy-like small blossoms throughout spring, summer and fall. It is a hardy plant that can be cut back hard and it will bounce back prettier than ever. Seaside daisy attracts syrphid flies, bees, butterflies and lacewings.

California aster, Aster chilensis, is a shrubby and deciduous perennial that blooms summer through fall. California aster attracts bees, butterflies, lacewings, lady beetles and syrphid flies.

Yarrow, Achillea millifolium Californica, has clusters of tiny white flowers on feathery green foliage that have continued blooms summer through fall. Plant in a sunny location. Yarrow attracts bees, butterflies, lacewings, syrphid flies and parasitic wasps.

Slender sunflower, Helianthus gracilentus, gives more vertical height to the garden in addition to colorful and showy fall blossoms. This sunflower attracts bees, butterflies, lacewings, syrphid flies and parasitic wasps.

Plan on planting natives in the fall when, hopefully, we will experience winter rains that will help them become established.

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Mark asks: We have many large boxed sycamore trees in our neighborhood that were installed last year. Now their water has been cut off and they are appearing stressed. They are a large and expensive part of the landscape and it would be a shame to lose them. The question is: How can we save the trees during the drought?

First of all, run an “in-line” drip line around the base of the trees and in their root ball area. It is very important to make sure the entire root ball is receiving moisture. This method of drip irrigation should help them survive the drought.

An older method of drip irrigation was to install one drip emitter on each side of the tree. This method will not give enough moisture to the entire root ball and will do little to alleviate their stress. This is also the case with any newly planted tree when it is of the utmost importance to protect your monetary investment and visual enhancement by giving it the best care and enough moisture until it has had enough time to become established, which can take several seasons. Of course, the important goal is to alleviate the trees’ stress from lack of moisture, keep them healthy and to avoid wasting excess water.

Mulch heavily to help retain the moisture and do keep the mulch a few inches away from the trunk. You should manually check the soil for moisture and adjust the amount of water on the drip line accordingly.

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to The Garden Doctors, at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.