|Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, August 11, 2007
“The Heat Lovers, Where Are They?”
We have not had a typical South Texas summer, what with near record
rainfall amounts and very cool temperatures, but it is interesting
to take note of what is blooming in our landscapes in this atypical
Crape myrtles were slow to begin blooming this year but they
sure have made up for it in recent weeks. In a previous article,
we discussed powdery mildew and sooty mold. Other factors that
affect plant health and bloom are lack of sun and poor drainage.
If your crape myrtles have been overgrown by shade trees or even
shrubs for the smaller selection, you can increase bloom by opening
them up to more light. Crape myrtles in shrub borders become covered
with vines and lose leaves. This year with all the rain, coral
vine, morning glory, green briar, cat’s claw and other aggressive
vines are overrunning some landscapes. They shade out the crape
myrtle leaves, the leaves drop and there is less bloom.
In a few cases, the soggy soils have caused root injury in plants
that are planted in low or poorly drained areas. The symptom in
less severe cases is small reddish leaves. The instinctive reaction
is to fertilize but that is not a good way to address the problem.
The salty fertilizers just stress the injured roots further. An
established plant will probably recover on its own. For crape
myrtles planted in the last three years you may have to move them
if you are going to have a healthy plant. Crape myrtles are drought
tolerant and require well drained soil to prosper. If they were
planted in a low spot during the two years of drought, soggy soil
was not a problem. Now it is and will be in the future.
The poincianas have not liked this wet cool weather much at
all. The glow-in-the-dark orange/red/yellow blooms are just becoming
noticeable in area neighborhoods. Pull off any vines that have
overgrown them. If the sunny warm weather persists through September,
they should still make a show and provide nectar for hummingbirds
Vincas are usually the mainstay of summer flower beds in South
Texas. This year has not been good for the drought tolerant, sun
loving species. They are susceptible to the disease aerial phytophera
that results when the foliage stays wet due to rain, humidity,
or overhead sprinkling. Many beds of vincas planted in May or
June succumbed to the phytophera by disintegrating into a pile
of mush. The good news is that it looks like the constant rains
have ended and vincas should survive and bloom until November.
Chaste tree (vitex) has bloomed well but you may not notice
the blooms this year. The foliage has been growing at the same
time and the flowers are partially hidden within the new growth.
The hummingbirds and butterflies have been able to find the blooms
and they should be more visible this fall.
Texas sage (ceniza) has been invisible in the six weeks of rain.
It performs best in dry periods with infrequent rains. Newly planted
ceniza is especially susceptible to root damage due to soggy soil.
If your ceniza is planted in a low spot it may experience a leaf
drop. It does not need fertilizer and in fact, an application
of salty fertilizer will add to the problem. Let them recover
on their own.
Lantanas have also responded to the heavy rains with a flush
of growth at the expense of bloom visibility. They should make
a great show this autumn.
Esperanza is also taking advantage of the rain and mild temperatures
to grow foliage. The plants are lush and full. Somewhere within
the thick growth are the blooms. Like lantana and chaste tree,
expect a great bloom period this fall I we can have some normal
dry, sunny weather.
Both old fashioned and modern roses often take a break from
blooming in July and August. This year they have had weather that
could have supported blooms all summer but foliage disease pressure
has been so strong that most varieties have lost foliage. If the
leaf fungus did not reduce bloom, the heavy rains took a toll
on the buds and flowers.
This autumn could be spectacular for all roses if it dries out.
Fertilize your roses with one cup of slow release lawn fertilizer
per plant and begin your spray program.
Organic gardeners have a new tool in the arsenal to protect
roses from insects, Spinosad. Neem Oil and sulphur products are
organic controls for fungus. Acephate and Funginex are the usual
manufactured sprays for controlling pests on roses. Old fashioned
roses and the tough modern roses like Belinda’s Dream and
Knockout do not require a spray program most years.