The past spring has been cool and wet, with excessive amounts of rainfall. On April 19, we saw several inches of rain caused floods in parts of the county. However, the weather has now become hot and dry, and the forecast for the next week indicates more of the same with record temperatures well into the 90s.
What can you do for the plants in your landscape to help them through the type of weather we are having?
When applying water, ensure it reaches deep into the root zone. Shallow watering causes the roots to grow in the top couple of inches in the soil that increases the plant’s susceptibility to environmental stressors and pests. The rule of thumb is to apply one inch of water per week. Home lawns should be watered once or twice a week to ensure they have the necessary amount of water and that it penetrates the lower roots.
The same is true with herbaceous annuals and perennials as well as vegetables. When applying water, do so earlier in the day, and with plants other than lawn grasses, direct the water to the base of the plant and keep it off the foliage as much as possible to reduce diseases. For trees and shrubs that are well established, in most cases, supplemental water is not necessary since they have deep root systems.
The soil needs to be kept evenly moist, meaning that it should not be going form the extremes of too dry and excessively wet. In tomatoes and some other vegetables, a condition called blossom end rot can occur where the bottom end of the fruit rots. The cause is the plant’s inability to absorb the calcium due to the uneven soil water even if the soil has ample plant available calcium.
One of the best methods to ensure the soil has enough water is the application of a fine-textured organic mulch such as pine straw, pine bark or cypress mulch, one to three inches deep. It will hold moisture and has the added benefit of reducing weeds. Avoid using lava rock, marble, or gravel since these materials radiate heat absorbed from the sun and can cause heat damage to most plants.
Avoid fertilizer applications during prolonged droughts. Excessive applications can burn the plants as well as increase their need for water. Also, avoid any heavy pruning of the plant material. However, sometimes selective pruning may be necessary when a plant begins to wilt and has leaf scorch along with dead branches. The pruning helps reduce its foliar demands on the roots for water and keeps the roots alive.
Also, cut back wilting herbaceous annual and perennial flowers to reduce their moisture loss. Fertilization and excessive pruning encourage new vegetative growth that has a greater need for water and wilts during prolonged dry spells, thus increasing the overall requirements for water.
Despite the unseasonably hot and dry weather, steps can be taken to reduce the stress on your garden plants. Hopefully, we will not suffer these conditions all summer, but a little preparation can do a lot of good.