Hunt County Master GardenersTexas A&M AgriLife Extension Service

Cypress Trees as Landscape Trees

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Cypress Trees as Landscape Trees by PJ LaRue Smith

Stately and intriguing, the mature Bald and Montezuma Cypress trees leave one with a sense of awe and curiosity.  While these two trees are very similar to one another in general appearance, there are significant differences that bear mentioning, especially if one is planning to add either to their landscape.

More commonly seen (in this area of Texas) is the Bald Cypress (Taxiodium distichum).  Native to the southern part of the US, the Bald Cypress is unlike other members of the cypress  (Cupressaceae, a type of conifer) family, in that it is deciduous (looses its leaves) during the winter.  This tree is not without winter interest, though, as the rust-brown leaves and round seed pods remain on the tree throughout much of the season.  Naturally growing in wet, swampy areas, the Bald Cypress thrives in areas where most others do not, making this tree an excellent choice for a low, wet area of the landscape, and alongside a pond or stream.  But the Bald Cypress does not have to be planted in a wet area, it can grow quite happily in most areas of a landscape with little difficulty.  Chlorosis can be a problem in soils with a high pH, so test the planting site if this may be of concern.  Growing to a height of 50 to 70 feet, with a 30 foot spread, the Bald Cypress is pyramidal in habit, with a heavy straight trunk, and branches that are distinctly horizontal.  The foliage is spirally arranged along the stems and, unlike most conifers, is soft to the touch. New growth in the spring is a very light green, turning to a darker shade of green during the summer.  The wood of the Bald Cypress contains chemicals that resist attack by fungi making it desirable for use in exterior trim, boat and ship building, shingles, posts, poles, etc.

The most unique feature of this tree, and one that needs considering before planting, is its “knees” – protuberances that arise from the roots that can get as tall as three feet!  While the purpose of these knees has never been scientifically confirmed, the two main suppositions directly relate to the tree’s native habitat – swamps and water courses. The most common reason one will hear is that the knees provide a way for the roots to exchange oxygen and other gases.  The second reason is that these knees provide the tree with further structural support in a more vertical manner than the lateral roots do in the wet, loose soil.  Whether it is the first or second reason, or even a combination of the two, these knees certainly add a novel look to the landscape around a Bald Cypress tree, being a source of curiosity for both young and old alike.  The caveat here, of course, is that running over these knees with a lawn mower will be neither beneficial for the tree, or the machinery.  Be sure to locate this tree in an area where the knees will not be a source of aggravation, and both you and the tree will be happy.

Montezuma Cypress (Taxodium mucronatum) trees are native to deep south Texas into Mexico and a close relative of the Bald Cypress.  However, there are significant differences between the two species of trees.  The Montezuma Cypress (a) is evergreen in its natural range  (deciduous north of that range); (b) is not prone to grow “knees”; (c) grows taller and faster than the Bald Cypress; (d) is somewhat cold sensitive; (e) has a broad, spreading crown; and (f) has strong, horizontal branches, but delicate branchlets that droop downward giving the tree a distinctive weeping appearance.  It is this “weeping” look that makes this tree very attractive in the landscape, and if grown in a drier site, there should be no “knees” to worry about mowing over.

Both of these trees make wonderful additions to the landscape as long as their location is considered carefully before planting!

 

Oak Tree Diseases

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Oak Tree Diseases by Byron Chitwood

Probably the most dreaded disease problem that attacks oak trees in Texas is Oak Wilt.  Fortunately, we do not have that problem in Hunt County.  However, it is as close as Collin County to the west of us so be vigilant and take precautions to prevent this disease from attacking your oak trees.  It can attack any variety of oak trees but seems to be one that infects Live Oaks.  One of the easiest precautions that can be taken is to buy only seasoned fire wood, preferably from this immediate area.  Also, do not trim any of your oak trees except in the hottest and coldest month: August and February respectively.  The spoor that causes oak wilt is transmitted by a small beetle that feeds on the sap of trees and can smell a newly cut tree from over a mile away.  In order for the oak wilt spoor to infect a tree it must be transmitted in a fairly mild temperature range.

The disease that has been the most prevalent in this area for the last several years is Hypoxylon Canker.  This disease is transmitted by windblown spoors from an infected tree to other ones especially those in a distressed state such as we have been witnessing as a result of the extended drought.   Post oaks are the variety most affected by this disease. This area has a lot of post oaks, especially in sandy areas.  Post oaks have a relatively shallow root system which does not hold water very well.   Drought conditions dry out the topsoil very quickly and leave the trees in a very distressed and vulnerable condition.  If there is Hypoxylon canker infected trees in the area, the spoors are transmitted by the wind and can infect ones that are not already infected.

The first signs of Hypoxylon canker are peeling of bark from the infected tree.  These spoors have somehow gotten under the bark and feed on the trees vital fluids.  The canker grows under the bark creating pressure causing the bark to burst and fall off.  The tree cannot survive if the tree is “girdled” and will very quickly die.  There is no known cure for a tree in this condition.  The best way to prevent trees from contacting the disease is to keep the “high value” ones watered.  These are the ones in yards and close to homes.  If a large acreage is involved, there is not much that can be done economically to prevent the disease from occurring.

Post oaks are very sensitive to root damage.  Do not grade or fill with topsoil on the root system.  Do not park vehicles on the root system.  If a tree dies from Hypoxylo0n canker, cut it down and stack away from other trees.  Cover with a clear plastic sheet and the heat will kill the active spoors.  It can be safely burned without transmitting the disease.

There are too many tree diseases to describe them all in this article.  If you do have a tree problem, contact the Texas A&M AgriLife office at 903-455-9885 with a description of the tree problem and the variety of tree if available.  The office will alert one of the local Master Gardeners and you will be contacted with advice on what the problem is and how to handle it if there is a solution.

Planting Bare Root Plants

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Planting Bare Root Plants by Madeline Sullivan

When you are thinking about planting a tree you need to consider how big your tree will grow. Avoid planting under or near overhead utility lines, and check for underground utilities, too. Then, make your decision to plant a nice tree that will grow healthy and vigorous for the length of its natural life.

If you have a bare-root tree it is best to plant it immediately to keep the fragile roots from drying out.  If for some reason you cannot plant the tree quickly because of the soil conditions or the weather, put the tree in a sheltered, cool place and keep the roots moist. Once you start to plant your tree, take off the packing and get rid of all the packing materials that are around the roots. Soak the roots in water three to six hours. Most important, do not let the roots get dry.

Now you can start digging the hole to plant the tree. Make the hole much bigger around than seems necessary, so the roots will have plenty of room to spread-out and grow. Get rid of all the grasses in a 3 foot circular area. Then, turn the soil in an area up to three feet in diameter.  This is to aid in root growth. Hold up the tree and position it in the center of the hole. Make sure that the tree is at the same depth it stood in the nursery. After planting, the root flare must be above the ground level. Again not crowding the roots, partially fill with the soil that was dug from the hole. Firm it around the lower roots. Do not add anything, such as peat moss or bark. Put in the remaining soil, firm the soil, but not tight. Make a water holding basin around the tree. Give the tree plenty of water. Let it soak in. Then, mulch to a depth of 2-4 inches with organic material such as wood chips or bark pieces. Put the mulch in an area three feet in diameter around the tree, but do not let it touch the trunk.  Generously water the tree every week or ten days, in dry weather, for the first year. Water slowly and do it at the drip line of the trees canopy.

A young tree’s best friend is mulch. It retains moisture, prevents grasses from getting around the tree, insulates the soil, prevents soil compaction, keeps down lawnmower damage, and makes an aesthetic look to a yard or street. In the spring, remove some of the mulch that may be three to four inches deep. Two inches is good around the tree until it is well established. One of the main errors in planting that cause bare rooted trees to die is planting too deeply.   As mentioned before in this article the root flare must be above the level of the soil after the soil has had time to settle.

Pine – A Versatile Tree

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Pine – A Versatile Tree by PJ LaRue Smith.

From needles to trunk, the pine tree (a member of the Pinaceae family) benefits man in a multitude of ways. To gardeners, the smell, symmetry (or lack of, in some cases), and it’s status as an evergreen, provides the incentive to grow this stately tree in their landscape.

While there are many varieties of pine available for use in the garden, the focus in this article will be on the Loblolly pine (Pinus taeda), a native Texas variety that is commonly grown in the Hunt County area.

The optimum growing conditions for the NATIVE loblolly pine are full sun, moderate moisture, neutral to slightly acidic loam or sandy soil. However, through years of research and specialized hybridization, the Texas Forestry Service has developed hybrid loblolly pines that are more tolerant of drought and are able to grow in a variety of soil types. With minimal care, these hybrids are capable of growing as much as 2 – 4 feet per year. An added plus, as noted by this author, is the perfume-like fragrance some of these hybrids produce.

What other benefits can one gain from growing pine trees? For the gardener, there is the added benefit of “pine straw” (needles) that fall in the autumn/winter months that can be used as a mulch for the garden. Pine straw mulch increases soil acidity (to a degree) in certain soils and, unlike pine bark, pine straw will not “float” away as easily during a heavy rain. Another added benefit arrives in spring when the worm population infiltrates the pine straw – loads of worm castings! The benefits of pine straw use in the garden has brought about it’s harvesting into bales in east Texas and other southern states.

At this time of year, another benefit of the pine can be found as Christmas decorations everywhere –pine cones. A favorite collection item for both children and adults alike, the pinecone has many uses. It’s seeds can be germinated for more locally acclimated pine trees. Dry pinecones make a great fire-starter. And, as mentioned above, they are used in making homemade crafts for the holidays.

As a pine grows, the lower limbs often will die back so that the tree can focus it’s energy to the newer top-growth. If these lower limbs are removed soon after they die back, they can be made into fairly decent walking sticks or canes. If a mulching machine is available, limbs and twigs can be also be mulched and used in the garden or added to the compost pile.

Pine trees that are no longer of use in the landscape, are overcrowded, or that meet an early demise due to an ice or snow storm (i.e. winter of 2000) can either be sold or taken to a sawmill for harvest into boards.

Interested in reforestation of an area? There are several sources for purchasing large quantities of young pines at minimal expense available. Visit the Texas Forestry Service website  or contact them directly via the number listed there for further assistance on pine tree sources or questions on reforestation.

Southern Pine Beetle

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Southern Pine Beetle by Stephanie Suesan Smith Ph.D.

Ever notice lots of oozing wounds on your pine, cedar, or juniper tree? See rows of circular holes in the trunk? You have crossed paths with the Southern Pine Beetle. Now this may be good news if you want the cedar in your pasture to die, but if you happen to like the tree that is infected, you have a problem.

Pine Bark Beetle Damage

Pine Bark Beetle Damage

The Southern Pine Beetle is a type of bark beetle. It bores a hole in the bark of the tree and lays eggs there. When the eggs hatch, the grubs, or larvae, chew the wood around the hole they are in. The newly hatched ones eat the soft, inner bark. The older ones eat the harder outer bark.When it has grown enough, the grub pupates and changes into an adult. The adult chews a circular hole through the bark and flies off to find a mate.

The beetle kills trees by either girdling it or by simply sucking so much of the needed water and nutrients the tree starves. Often, the first time a homeowner sees a problem is when the crown of the tree turns yellowish, then red, and finally brown. By then, it is very difficult if not impossible to treat the problem.

Other signs that there is a problem are tubes of pitch, or resin, flowing from the tree. When first attacked by these beetles, trees often exude large quantities of pitch in an attempt to push the invaders out. Sometimes this works. Other times, it does not, or the tree is not able to mount this counter attack.In any case, such pitch tubes are signs of a problem and should be investigated further.

The beetles and their larvae are small, about 1/8 inch long. If you chip the bark off a suspected invasion site, you will see holes with tiny grubs in them. You may see the black adult beetles, as well.

If you have this problem, you will want to treat it promptly so other trees do not become infected. How you treat it depends on how severely the tree is infested and what symptoms it has developed. If the crown is brown, your tree is probably dying and should be cut down and burned as soon as it is cut to kill the larvae and beetles it contains.

If your tree is at the pitch tube stage, or the crown is still green, you may be able to save it. The district entomologist has had some success with using Bayer Advanced Tree and Shrub Insect Control. This is a drench you mix in a bucket and pour all around the tree. The tree takes up the drench as if it were water. When the larvae and beetles suck the sap from the tree, the poison kills them. Be sure to follow the label directions and be advised that this is not as successful with heavy infestations.