How is your garden weathering this heat wave?
The best care is prevention, watering extra up to a week ahead of an anticipated hot spell. But if you didn’t have the chance to do this, here are some tips for during and after the hot weather:
1) Overhead water your plants in the early morning or late (very late) at night. Yes, you can get out the hose and hand spray! Plants have tiny openings, called stomata, on their leaves (mostly), and plants from Mediterranean climates are adapted to close their stomata during the afternoon and early evening hours, when temperatures and winds are at their peak. They open them, allowing water both in and out, as the temperatures decrease. If they are well hydrated, the water-out part cools them off.
2) If you have sandy or gravelly soil, deep soak the soil to the root zone, several feet down in addition to foliage-spraying.
3) If you have heavy soil with clay, spray off the foliage, but water the soil only in extreme cases, in the early, early morning, and don’t over soak the soil. Adding water to clay soil that is warm (as in summer) is always a gamble, as this is what causes root and crown rots that can kill your plants quickly. Try the overhead spray first, by hand, every morning of a heat wave, and try to leave the soil water on whatever automatic schedule has been working before the heat wave.
4) Mulch keeps soil cool and reduces evaporation, but keep mulch a few inches away from woody crown and trunks.
5) By afternoon, native plants have closed most of their stomata, so it is less effective to hose them off then.
6) Established native plants may show signs of stress, including dull leaves or yellow leaves and dropping leaves. This doesn’t mean the plant is dying. Monitor, but don’t panic and pour on the water, esp. if you have clay-mix soil.
Hope that helps!