How to tell if your plants are water-stressed out – Record Searchlight

Leimone Waite, Master gardeners Published 5:00 a.m. PT Aug. 14, 2020

Make sure you follow these 3 tips for a healthy vegetable garden. USA TODAY

Q: What is wrong with my hydrangea? The outer part of the leaf has suddenly turned a lighter green while the middle part of the leaf is dark green. This is happening to most of the leaves on the shrub.

A: This sounds like the classic symptoms of water stress, especially given the very hot temperatures we had this past week.On these hot days the soil dries out and plants wilt and then are watered and rehydrate;however the cells in the outer margin of the leaf have suffered too much damage to fully recover. Because the damage occurs so fast, plants are not able to relocate chlorophyll to other leaves so the damaged portion of the leaf retains a dull green color.

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Even if your yard is receiving regular irrigation, on really hot days the water requirements of plants can dramatically increase and you may need to increase watering accordingly. I have plants in potsI have to water twice per day on days when temperatures are over 105 degrees and it's windy. There are ways to help manage the need for extra watering, such as moving potted plants into the shade on hot days, or mulching around plants keep them from drying out as quickly.

The first signs of water stress in landscape plants and trees include wilted or drooping leaves that do not return to normal once temperatures cool at night, curled or yellow leaves that may fold or drop, leaves that change to a grayish or bluish green color, sunburned leavesand new leaves that are smaller than normal.

Ornamental grass or lawns may show water stress by changing to a bluish gray color rather than a vibrant green or have wilted blades of grass. As things dry out further, the tips of the grass may turn yellow and then eventually brown. Another quick check to see if the lawn is water stressed is tosee if the lawn grasses retain a footprint for several minutes. If theydo, the grass needs more water. If these hot temperatures persist and the lawn does not receive adequate water, it may gradually turn brown and go dormant.

Monica Ho, Mai'Ana Airport Plaza manager, takes pride in growing vegetables and succulents in a garden she created at the 78-unit apartment complex in Tamuning on July 29, 2020. Pacific Daily News

The good news for your hydrangea is that it should recover as long as it continues to get adequate water. You may want to remove leaves that are heavily damaged, being careful not to remove the leaf bud at the base of the leafas these will grow into new leaves. You can fertilize the plant to help with new leaf growth, but choose a low-nitrogen, slow-release fertilizer and use at the lowest recommended rate. Too much nitrogen fertilizer stimulates rapid growth and increases the need for more water, causing even more stress to the plant.

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Once this heat spell is over, dont forget to dial back your irrigation timer, as overwatering can be just as stressful to plants as under watering. Signs of overwatering include drooping leaves or lower leaves becoming yellow and dropping, and lawns that feel spongy or turn yellow.

Master Gardeners(Photo: Master Gardeners)

You can find additional information for managing water stress in the University of Californiapublication Keeping Plants Alive under Drought or Water Restrictions. It's free to download at https://bit.ly/3akWnyp.

The Shasta Master Gardeners Program can be reached by phone at 242-2219 or email mastergardener@shastacollege.edu. The gardener office is staffed by volunteers trained by the University of California to answer gardeners' questions using information based on scientific research.

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How to tell if your plants are water-stressed out - Record Searchlight