And the Benefits of Mulching
"The edges of my leaves are drying and the entire plant looks
like it is dying." What can I do? This is a common complaint
during the hot, dry summer season. The problem is leaf scorch.
Leaf scorch is caused by one or several factors.
Drying wind - During periods of high, dry winds,
moisture is removed from foliage faster than the roots can supply
it. The result is scorched or withered foliage. Only protection
from the wind can help in such cases.
High light intensity - Some plants cannot stand
the bright sun of mid-summer in Texas. This is particularly true
of trees and shrubs not adapted to the local environmental conditions
such as most magnolia, dogwood, azalea, and maple.
Insufficient soil moisture – During dry seasons,
watering should be very thorough. Merely sprinkling the ground
around a plant until the surface is wet is inadequate.
When water and leaf scorch are mentioned together,
many people think that water beads on the leaf surface act as
a prism to concentrate the sun's rays and burns sections of the
leaves. This is a totally false notion. First, the water droplets
would have to form and retain a deep bead in order to generate
a prism ray. Second, if such a ray could be generated, the damage
would be a very distinct, circular shape rather than a scorching
of the leaf's edge.
Last year, area nurserymen were challenged to produce
one single case of leaf scorch caused by watering during hot weather.
Not one single example could be found. Watering with scalding
hot water will, of course, cause foliage burn, and there is some
evidence that watering a drought-stressed plant with cool water
can cause leaf bleaching, but the theory that watering in hot
weather scorches foliage because of water acting as a prism is
Many times, newly established plants have not generated
enough root system to uptake sufficient moisture to offset the
rapid loss of water that occurs during hot, dry weather. Trees
that are over 6 feet tall when they are planted are particularly
susceptible to this problem. They should now be pruned back significantly
(at least 1/3 of top removed) if they haven’t been cut back
already. The foliage of affected trees should be sprinkled with
a mist of water 2 or 3 times a day. Apply a layer of mulch around
the base of the tree to stabilize water loss in the root zone.
Simply put, mulch is a layer of material covering
the soil surface around plants. This covering befriends your plants
in a number of ways.
- It moderates soil temperature and therefore promotes
greater root development. Just like people, plant roots prefer
to be cool in summer, warm in winter, and they can be, under a
year-round blanket of mulch.
- It reduces evaporation of water vapor from the
soil surface thereby yielding three important benefits. First,
it moderates the levels of soil moisture, promoting root growth.
It also means you don't have to water as often, which reduces
both your workload and your water bill.
-Mulching reduces washing and crusting of the soil
during natural rainfall or irrigation. Falling drops of water
can pound the upper 1/4 of soil, especially a clay soil, into
a tight, brick-like mass that retards necessary air and water
movement to the root zone.
- It reduces disease problems. Certain types of
diseases live in the soil and are spread when drops of water splash
bits of infested soil onto the lower leaves. Mulching, and being
careful when you water, can reduce the spread of these diseases.
Mulching will also keep fruit clean while reducing rot diseases
by preventing soil-fruit contact.
-I've saved the best for last. Most weed seeds
require light to germinate so a thick mulch layer will shade them
out, and your weed problems are reduced by at least 90%.
What can you use for mulch? Any plant material
that's free and not diseased can be used. Weed-free hay or straw,
leaves, grass clippings, compost, etc., are all great. Fresh grass
clippings are fine for use around well-established plants but
they should be cured for a week or so before being placed around
Mulch vegetable and flower gardens the same way.
First, get the plants established, and then mulch the entire bed
with a layer 3 to 4 inches thick. Work the mulch material right
up around the stems of the plant. When you finish, you'll have
a beautiful, even expanse of mulch highlighted by healthy, productive
Recent research indicates that mulching does more
to help newly planted trees and shrubs become established than
any other factor except regular watering. Grasses and weeds, especially
Bermuda grass, that are allowed to grow around new plants are
terrible thieves of moisture and nutrients. Mulch the entire shrub
bed. For new trees, apply mulch in a 4-foot circle. The layer
of mulch should be 3 to 4 inches thick.
The epitome of effective hot weather gardening
is the combination of drip irrigation and mulching. Simply cover
the irrigation lines with mulch to reduce water usage, disease
problems and gardening effort while you increase root development
and plant performance. That's how to garden smarter, not harder.