We’re hot here at the nursery and we're sure you are too. Here are some important tips we wanted you to have.
Newly installed plants are among the highest priorities for watering during a heatwave. These plants have not rooted into the ground completely and are at a greater risk of drying out during times of excessive heat. Water new plantings deeply, using soaker hoses, drip systems or sprinklers.
Deep watering entails watering at a slow pace for long enough that the water soaks deep into the soil, where the roots are. Often this means watering for 30-60 minutes at a time, 2-3 times each week, until plants are established. When temperatures normalize, continue with deep watering, but back off to 1-2 times each week.
Tree bags are fine to be used for newly planted trees, but only for short periods of time. They should be removed between waterings to avoid causing rot at the base of the tree’s trunk. Tree bags are not effective for watering established trees, because the roots of a mature tree extend far beyond the trunk.
Shading newly planted areas with umbrellas or shade cloth can really help to reduce heat stress.
Plants in containers dry out faster than plants that are growing in the ground, and during a heatwave they may need watering more than once each day.
When you know an extreme hot spell is coming, it can help to move smaller containers into shaded areas just for the duration of the hot weather. Hanging baskets can be helped by placing them on the ground.
Hanging baskets and containers of annuals lose a lot of their nutrients when they’re watered this often, so it’s a good idea to fertilize after the heatwave is over.
Even the most established plants in our gardens appreciate a deep soaking a few times during summer, and indeed fortifying them with a long slow watering before a heatwave is a good idea. It’s important to apply water to the whole root zone, which reaches at least to the dripline of the plant.
Use a soaker hose or sprinkler for 30-60 minutes at a time. During normal summer temperatures, this type of watering can happen every 2-3 weeks. In times of extreme heat, 1-2 times each week may be necessary.
Know your plants though! Some plants prefer almost zero water during summer (manzanita, Ceanothus, madrone and cistus) and others wilt even when they have ample water (hydrangea, rhododendron). So adjust watering accordingly.