The heat is on here in the
High Desert. During these hot summer months, I try to get out and do my
gardening chores early in the morning to avoid the intense heat of the day.
Since it is easy to find yourself out in the yard longer than intended, it is a
good idea to apply a good sunscreen, and wear a hat and light-colored
loose-fitting clothes to help prevent sunburn. And, don’t forget to stay hydrated
by drinking plenty of fluids – my preferences are water, unsweetened ice tea or
coconut water.
Heat and sunlight not only
affect gardeners, they also have an effect on plants.
Leaves can become sunburned
and begin to get large yellow patches that turn gray or brown in the center. If
plants showing signs of sunburn are in pots or containers, move them to areas
where there is more afternoon shade. If the plant(s) are planted in the ground,
it may be necessary to erect some form of shade cloth protection on the south
and west sides of the plant. If certain plants become too stressed in the
summer, it might be a good idea to consider moving the plant to a more suitable
location in the fall or early spring, or add protective, shade-giving plants to
the existing landscape.
Sunscald on trunks can lead
to disease problems and even death. This most often happens on young trees that
have not yet developed a true bark. To help prevent sunscald, apply a coat of white
interior latex paint that has been mixed with water to make a half paint- half
water mixture – sunscreen for plants. There are also fabrics available at
nurseries and garden centers designed to wrap around a tree trunk to help
prevent injuries, including those caused from too much sun.
Some plants may show signs of
drought stress, which appears as yellowing and browning leaves, but not in
patches like sunburn. Plants will also begin to wilt. Make sure that trees are
getting deep watered to a depth of three feet, shrubs to two feet, and ground
covers to one foot. It is best to deep water less often than to frequently water
just the surface. Also take note that most of a plant’s water-absorbing roots
are located around its dripline (edge of its canopy), so make sure to apply
most of the water in this area rather than around the trunk or stem. Once the
soil has dried to a depth of two to several inches, apply more water.
Some plants prefer dry
summers and are prone to rot problems if given too much water in the spring.
Many of these plants are our California native species, which are adapted to
winter rainfall and dry summers. If such a plant is showing signs of wilting,
and it has been watered regularly throughout the summer, check to see if the
soil is moist. If it is moist, discontinue watering until cooler weather comes
along and see if it begins to improve. These types of plants can be susceptible
to root rot fungi that become damaging when conditions become warm and moist.
Wilt symptoms appear because the rotting roots can not longer take up the
necessary water. Allowing the soil to dry out a bit can help promote new roots
to grow and the plant to recover.
So remember that plants can
be affected by the summer heat just as we are. Sunburn and dehydration can be
prevented if care is taken to make sure that adequate shade, sunscreen and
water are used. Since the amount of water we use is an issue here in the
desert, it is a good idea to consider the use of native and desert adaptive
landscape plants that don’t require lots of summer irrigation.