Gardening

Milkweed assassin bugPhoto by William Johnson
The milkweed assassin bug is a commonly occurring                                                                             beneficial insect in local gardens and landscapes.                                                                                         Meet several more in a free public presentation being                                                                                     given by Post columnist William Johnson next Tuesday.                                                                                   For details, see At A Glance, below.

Johnson, William               William Johnson

THE EXTENSION fruit & pecan committee, master gardener volunteers and Galveston County AgriLife Extension office will co-sponsor a fruit orchard and garden tour on Saturday, May 16, from 9:00am to 12:00 noon. The program is open to the public and free-of-charge.
Three fruit orchards are on this year’s route and each will be open during the tour period. You will have the option of touring all three sites or any combination at your own pace and in any order you choose.
This year’s tour sites contain a wide variety of fruit trees, ranging from an impressive fruit tree orchard at Fruits ’N Such orchard at 6309 Avenue U & Bowerman Drive in Dickinson to the master gardener demonstration orchard in Carbide Park in La Marque. Peach, plum, citrus, fig, apple and other fruit trees can be seen also.
All three sites contain a wide variety of vegetables. They are grown in dozens of raised beds at Carbide Park, whereas they are grown in the ground at Fruits ’N Such.
Visitors may also tour an impressive herb garden next to the Fruits ’N Such orchard. If you’re looking for the freshest produce to purchase, you can pick it yourself at Fruits ’N Such.
If you are interested in seeing the amazing diversity of fruit trees that can be grown in a backyard, be sure to include a tour of master gardener Bill Verm’s home orchard in Santa Fe.
If you have an interest in roses, be sure to visit the display beds of earth-kind roses at the Carbide Park site. Homeowners love their magnificent blooms and fragrance.
Roses have had a centuries-long reputation of being the most neurotic members of the plant world. Consequently, gardeners spend considerable cash buying fertilizers, pesticides and fungicides to sustain their roses, and much time pruning, deadheading and watering them to keep them blooming. Roses that qualify for the earth-kind designation are very low-maintenance and perform very well under a variety of growing conditions.
To obtain a map with directions to the tour sites, visit Galveston County AgriLife Extension office in Carbide Park, at 4102-B Main Street in La Marque, or call 281-534-3413, ext 1-1.
A printable copy of the tour map and additional details are available on my website, the address for which is provided with this column (click on the “Extension Educational Programs” link).
Area homeowners who grow – or plan to grow – fruit or vegetables for home use will find the tour sites to be of considerable benefit.

At a glance

WE OFTEN find bugs annoying but there are lots of insects and other critters that help keep gardens and plants healthy. Local gardeners are likely to name lady bugs or honey bees when asked to give an example of a beneficial insect commonly found in Gulf Coast gardens and landscapes.
Local gardeners would be surprised at the diversity of beneficial insects already residing – and working – in their backyards.
To learn more about beneficial insects and how to identify them, preregister for an upcoming educational program entitled Beneficials In The Garden And Landscape. The illustrated presentation will be provided by William Johnson at 6:30pm on Tuesday, May 19, at the Galveston County AgriLife Extension office in Carbide Park, 4102-B Main Street, La Marque. Preregister by e-mail to galv3@wt.net or by phone at 281-534-3413, ext 1-2.

William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm

Johnson, William           William Johnson

??????????                                Photo by William Johnson

Each of us can do something to help insects                                                                                           pollinate our garden plants, including honey bees.                                                                                    Simple actions, ranging from planting more                                                                                         pollinator-attractive flowers to using pesticides                                                                                             only when necessary and according to their label                                                                                 directions, can make a big impact.

A busy and challenging month

BUSY DAYS are in store for the May gardener in completing spring chores and preparing for summer, so here’s a guide that might be helpful for planning this month’s gardening activities.
A Home Fruit Growers’ Tour will be conducted on Saturday, May 16. Three fruit orchards are on this year’s tour, each of which will be open from 9:00am to noon.
This year’s sites contain a wide variety of fruit trees ranging from a peach orchard – Fruit ’N Such orchard at 6309 Avenue U, Texas City – to the master gardener demonstration orchard in Carbide Park in La Marque and a sizeable home orchard in Santa Fe.
Tour maps and additional details may be downloaded from my website address, which is shown at the end of this column – click on the “extension educational programs” link. Additional information will also be provided in next week’s garden column.

Sensitive vegetables
The unusually wet and cool spring has delayed planting of many vegetables. Even tomatoes have had an unusually tough time this spring.
Normally, I recommend that okra be planted during April but this year it would have been better to have waited until May given the occurrences of cool temperatures over the past few weeks.
This cousin of cotton especially needs to be planted in a warm soil. Proven varieties include Emerald, Clemson Spineless and Jade. After planting, plan to thin plants to 24 inches apart in the row, with rows 36 to 42 inches apart.

Squash set
Don’t be concerned if the first several squash fruit fall off the plant before they reach an edible stage. The first flowers to form in squash in early spring are the females – those with the miniature fruit right under their yellow flowers.
With no male flowers being present, no pollination takes place. However, within a few days the male flowers will be formed and normal fruit set should take place.
Interestingly enough, it’s the reverse in summer plantings – the male flowers tend to develop first so no fruit set occurs until the female flowers develop.

New plants’ care
Spring- and winter-planted trees and shrubs will be establishing their root system this month and thus are very susceptible to transplant shock during the summer if not provided proper care during extended periods of dry weather.
The first summer of growth is a critical period for all newly planted trees and shrubs. To reduce transplant shock, be sure to water them thoroughly and deeply as needed during dry weather rather than giving more frequent, light sprinklings.
Plants should also be mulched with shredded pine bark or pine needles. A four-to-six-inch layer of mulch will also help control weeds, maintain more uniform soil moisture and keep the soil cooler. As a result, the degree of transplant shock will be significantly minimized.
Also, add to the list of benefits the fact that mulched trees and shrubs will grow much better than non-mulched transplants.

Summer annuals
For instant color, purchase already-started annual plants. Select short, compact plants. Remove faded blooms for more productive flowering.
If beds are not mulched, then lightly cultivate the upper soil so as not to disturb shallow roots. Doing so improves water absorption, reduces soil compaction and aids in weed control.
Plant annuals that take the heat such as periwinkle, purslane, portulaca and lantana.
Annuals for shade include impatiens, coleus, caladiums (the tubers are just about out of stock but potted plants are still available) and bedding begonias.
Caladiums will often produce a single flower stalk right after the first leaves are produced. Early removal of the flower stalk will encourage them to produce more lush leaf growth.

Pollinator protection
We are busy in the garden this month and so are honey bees and other insect pollinators. Let’s do all we can to protect these valuable little insects.
Many insecticides are highly toxic to bees. Some cannot be safely applied at any time that target plants are in bloom, while others should be applied during late evening, when bees are less likely to be foraging for nectar and pollen.

William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm

Johnson, William

THE SPRING ritual of phone calls and visits to the AgriLife Extension Office in addition to urgent e-mails submitted by county residents this time of year is proof that insect pests and disease problems on landscape plants can be expected to return with warmer weather conditions.
The following is a sampling of questions asked by local residents:
Q: My oak trees have been invaded by an army of caterpillars that are very hairy and quite colorful. Any ideas on the name of this caterpillar? Is this a stinging caterpillar? Should I treat my oak trees?
A: This year is shaping up to be an active year for caterpillars across Texas. Populations of tent caterpillars have been enormous in some areas of Texas. Tent caterpillars have caused dozens of blackouts in the Dayton, Texas, area when caterpillars moved from tree limbs onto high voltage transformers and caused electrical shorts. Galveston County residents are fortunate in that tent caterpillars rarely occur in this area.
The caterpillar that has alarmed local residents is commonly known as the Live Oak Tussock Caterpillar (scientific name is Orgyia detrita). The Live Oak Tussock Caterpillar does not form tents. While this caterpillar is known to occur in low numbers in most springs, residents in the League City and Friendswood area are reporting major outbreaks of this insect pest.
The good news is that a healthy tree or shrub can generally tolerate a total defoliation without suffering permanent damage. By the time homeowners notice the leaf damage on their oak trees, most caterpillars have stopped feeding and are entering the non-feeding pupal stage.
A mature caterpillar is about 1.25 to 1.5 inches long, with two long tufts of black hairs projecting forward from the head and a similar tuft of black hairs projecting backward from the rear of the body. Four dense patches of hair occur midway on the topside of the caterpillar’s body.
While Live Oak Tussock Caterpillars are not regarded as being stinging caterpillars, it is advised that people do not handle them. Some people aren’t bothered by the caterpillar but others could have a reaction that ranges from a mild to fairly severe rash. Parents are advised to keep an eye on their toddlers when outdoors to ensure that they do not make contact with the caterpillars.
I suspect that the abundance of Live Oak Tussock Caterpillars is correlated with the mild temperatures over last winter.
Q: The leaves on my oak trees have developed numerous bulges or bubble-like structures that eventually turn black. Some trees have lost most of their leaves. What causes this?
A: Our office has received numerous visits, e-mails and phone calls reporting similar symptoms on leaves of oak trees across the county. Your oak trees have a disease known as Oak Leaf Blister which is caused by a fungal pathogen.
Oak Leaf Blister causes small, rough (concave-convex) spots as leaves expand in spring. The spots turn pale green and become somewhat thick, then turn brown or greenish brown and eventually becoming black. Leaves with numerous spots will fall prematurely.
Control of this disease requires an application of a fungicide during early spring before new growth starts. It should be noted that once diseased foliage is present, fungicides will not “fix” the damage that has been done. Diseased leaves will simply fall naturally. Thankfully, it looks worse than it actually is. Since the tree’s health is not in danger, don’t be alarmed by this pesky fungus.
Once the blisters appear, the application of fungicide will be a wasted effort.  Fungicide applications (with products containing chorothalonil or mancozeb as active ingredients) used to prevent this disease would have to be applied in late winter before the tree buds begin to grow.   If Oak Leaf Blister is serious enough to cause leaves to fall, rake them up and dispose in curbside trash pick up.  Otherwise, go fishing!
I am not surprised by the widespread occurrence of Oak Leaf Blister this spring as this disease is favored by high rainfall during late winter and early spring when leaves are emerging.  In contrast, not a single case of Oak Leaf Blister was reported during the spring of 2011, which was a record drought year.

Photo by William Johnson
This year is shaping up to be an active year for caterpillars across Texas. While the Live Oak Tussock Caterpillar is known to occur in low numbers in most springs, residents in the League City and Friendswood area are reporting major outbreaks of this insect pest.

William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm

Johnson, William

Dealing with exposed tree roots

MUCH TO the dismay of homeowners, landscape trees sometimes grow roots above the surface of the lawn or possibly even buckle sidewalks and driveways. The roots not only affect the look of your landscaping but also present a tripping hazard to foot traffic and can make it difficult to mow the lawn around the tree.
Mature shade trees in the landscape are valuable assets in terms of increasing home property values, providing screening for reducing noise and lowering summer energy demands by shading living areas, etc.
The downside to beautiful shade trees is that surface roots sometimes pose problems as a tree matures. However, they deserve special consideration and care whenever digging, mowing or construction threatens to interfere with the roots.
When grown in landscapes, many shade trees form noticeable surface roots as they mature. The worst offenders are Arizona ash, oaks, sycamores, and pines.
However, even though tree roots appear to “come to the surface” (as many people believe), such is not the case. Although trees do send some roots down deep for moisture and stability, most tree roots tend to grow much more shallowly than most people think, with the majority found in the top 12 inches of soil. In fact, more than 50 per cent of a tree’s roots are in the top six inches of soil.
Large surface roots start out below ground as thin roots. As a tree matures and its primary roots age, the roots increase in girth, just as the tree’s trunk does. A small root that started out only a couple of inches below the surface can become visible as a monster four-inch-thick root on the surface!
Large surface roots start out below ground as thin roots. As a tree matures and its primary roots age, the roots increase in girth, just as the tree’s trunk does. A small root that started out only a couple of inches below the surface can become visible as a monster four-inch-thick root on the surface!
The problems worsen as the tree canopy shades the ground underneath, causing the lawn grass to thin out because of the reduced sunlight.
Bermuda grass does not tolerate shade well and St Augustine has the best shade tolerance of lawn grasses used in our area. However, even St Augustine will not grow in dense shade.
Thus, vegetation becomes sparse under large mature trees with dense canopies. Without some type of ground vegetation to hold soil particles, tree roots are further exposed by soil erosion.
Homeowners want to know what will happen if surface roots are just cut off – will it harm the tree?
Although this depends on how many roots are removed and how the job is done, the answer is almost always “yes”. A tree will suffer when its roots are damaged extensively.
People are surprised to learn that a tree has as much “growth” underground as it does above. It is important to understand that a single surface root is the origin of a very extensive network of feeder roots.
These feeder roots are a tree’s “vital lifeline” to the water and nutrients it takes up from the soil. The removal of one large surface root can result in the demise of thousands of feeder roots.
In spite of that warning, it may be necessary at some point to cut a surface root for safety reasons. Take the value of a particular tree into account when deciding how harshly to deal with its exposed roots.
Removing one or two surface roots should not be a problem. I would not remove too many large ones at once as this may place stress on the tree or even destabilize it. If a number of roots need to be removed, then you should do so over a period of a few years to give the tree a chance to regrow supporting roots elsewhere.
If a surface root absolutely must go, excavate the soil next to the root in order to make a clean vertical cut. Then remove the offending root.
After a tree’s root is cut, it would be a good idea to leave the cut end of the root exposed to the open air and not cover it with soil for two to three days.
This will provide sufficient time for the root to form a healing layer of cells over the wound tissue and to deter invasion by any fungal disease pathogens that might be present in the soil.
You don’t need to apply a pruning paint or fungicide. The tree’s natural healing ability will close the wound to infections.
As surface roots don’t just happen overnight, plan ahead. If some surface roots must be cut, the ideal time of year to do the job is January and early February, while the tree is dormant. After removing a surface root, help the tree recover by providing supplemental water during dry weather.
Solving the surface-root problem without surgery is a much better option. The area under a large tree can be planted with an attractive, shade-loving ground cover such as Asiatic jasmine, Vinca or mondo grass. To prepare the area, carefully break up the top one-inch layer of any compacted soil between surface roots with a spading fork.
The objective is to provide a gradual zone between compacted soil and the new topsoil, but don’t spade
deeper than one inch to avoid extensive injury to the tree’s feeder roots. Then spread a maximum of two inches of garden-soil mix over that.
Be certain to add no more than two inches of a good garden soil per year; tree roots can suffocate – and the tree may die – if more than that is added in a year. Also, sprinkle a light application of a general-purpose granular fertilizer (15-5-10, if possible; 13-13-13 would also be satisfactory) over the area.
Knowing that surface roots represent a potential headache, avoid planting shade trees closer than six feet to paved surfaces such as sidewalks and 15 feet from house foundations.
Some tree species seem to be more prone to surface roots than others. Unless you determine that you really need one, avoid choosing extremely fast-growing shade trees, most notably Arizona ash, silver maple (which I do not recommend at all for this area), poplar and willow, which develop surface-root problems sooner and quite extensively.
However almost any large, older tree in a home landscape will produce some surface roots. The notorious ones are probably just fast-growing species that bring the problem to the surface faster than others.

Photo by William Johnson
Of the many shade trees that form surface roots as they mature, the worst offenders are Arizona ash, oaks, sycamores and pines.

William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm

Amaryllis provides a dependable flower show

Johnson, William

AMARYLLIS is a popular bulb that is providing a stellar performance in many local landscapes over the month of April. Few flowering bulbs can surpass the stately beauty of the amaryllis.
Amaryllis readily adapts to our Gulf Coast landscapes and once established can become a long-lasting part of the landscape with minimal care.
Most plants in local landscapes are probably hybridized forms of amaryllis. This flowering bulb was first discovered by Eduard Poeppig, a young physician from Germany, while on a plant-hunting expedition in Chile.
Although we frequently see these beautiful plants for sale in pots around Christmas time, they can be raised very successfully out of doors in our mild climate.
Amaryllis grows from a large, multi-layered bulb that is very similar in appearance to the onion. It produces large, trumpet-shaped flowers, growing as large as eight inches across in clusters of two to six per stem. The leafless, hollow stems can grow to be two to three feet tall.
Although the dominant flower color of amaryllis growing in local landscapes is red, a range of other flower colors occurs, including shades of orange and pink as well as white.
Remove dead blooms before seeds are produced. If not, flowering the following season will probably be reduced. Removing dead blooms also helps to maintain the aesthetic value of the planting.
Amaryllis thrives in any reasonably good garden soil, including our gumbo clays, as long as drainage is good. Some garden articles recommend that amaryllis bulbs be planted in an area that receives part sun – about six hours of direct sun and then shade in the afternoon – but you are likely to see the flower thriving in full sun to part shade in our area.
Once planted and established, amaryllis can be left alone for years. A light sprinkling of a general-purpose fertilizer in March and June and watering during unusually dry weather are all they need.
Beds should be mulched with two-to-three inches of shredded pine bark or other similar organic mulch to help reduce weeds and conserve moisture.
Amaryllis may be dug and reset every September or October. While it is not necessary to dig, separate and replant each year, doing so will encourage uniform flowering and larger blooms. Digging also provides an opportunity to discard unhealthy bulbs, to increase your plants by removing and replanting young offsets – bulblets – and to amend the bed with organic matter.
The bulbs may also be left in the ground for several years – typically for two to four years of growth – then divided in the fall season. This is one tough plant and I have divided my amaryllis in late winter – February – with plants still producing a respectable mass of flowers in late spring.
Whether you’ve never had one or you have been growing them for years, amaryllis is a good investment for providing striking and dependable flower color in April landscapes.

Gardeners’ Q&A
Question: I have a grapefruit tree that I planted in February 2014. It is now producing an abundance of flowers. I was told by a friend to remove any flowers or fruits produced during the second year of growth.
Answer: Technically, the advice you received was sound. You will indeed increase future growth and fruit production by removing any flowers or fruits that the tree produces during its second year of growth. And a commercial grower with many acres of year-old citrus trees would be well-advised to thin out or eliminate flowers and small fruits during the second year of growth.
But let’s face it. We usually buy plants to enjoy. And, with citrus, much of the enjoyment comes from harvesting fruit from our own trees. I recommend removing nearly all fruits that set after flowering.
It would be satisfactory to leave two or three fruits on a tree to enjoy later in the year when grapefruits start to ripen on the tree. You would be able to experience an early sampling of what future harvests will be like.
This will also provide an incentive to the gardener
to continue to provide good care to the grapefruit tree over the upcoming growing season.

William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm

Photo by William Johnson
Few flowering bulbs can surpass the stately beauty of the amaryllis. It is a popular bulb that provides striking displays during April.