Summer heat stress is one of the number one tree killers I run into. Okay, realistically no tree ever dies from just one problem, but rather a cumulative affect of many stress factors. Heat and drought stress are stress factor that almost all trees in the central Texas area deal with on an annual basis. So, if your tree has some other factor stressing it out, the summer heat might be the straw that breaks the camel’s back. I see more trees die during the summer time than any other time of the year.
Crepe Myrtle with droopy leaves
Some trees suffer from heat stress more than others. For example, live oaks and cedar elms cope very well; sycamores and cottonwoods with will begin shedding leaves with moderate heat levels if water is scarce.
One important factor to consider when trying to quantify damage from heat stress is to take note of the date when your tree loses all its leaves. My experience has been that if a tree can hold its foliage through July into August then it will usually leaf out full the following spring. In some cases the tree will even put on a new set of foliage in September to effectively produce more sugars for itself through the fall growing season. Worst case scenario is if your tree succumbs to a heat wave in the spring. We’ll often get a hot spell in April or May that will reach 100F. If your tree loses all its leaves this early it probably won’t bounce back.
I get asked this question very often. Ball moss is something that we’ve all seen and are all familiar with, but there are still plenty of questions surrounding it and what it does.
To answer the age old question, you need to understand what ball moss is and what it isn’t. It is not a parasitic plant that is pulling nutrients out of your tree. It is in the Bromeliad family (so are pineapples). Ball moss is actually an epiphyte, similar to many mosses, lichens, algae and even ferns. It can grow pretty much anywhere…trees, power lines, on a wall, gutter or even that old car that has been sitting in your driveway for a couple of years now. Epihpytes derive their nutrition from the air and only need physical support from their host. Ball moss spreads by tiny seeds, which are carried through the air by wind, rain, squirrels and birds, which makes it near impossible to completely stop the spread of it.
Ball moss has been know to cause some minor physical damage to its host (trees). If allowed to grow unchecked for a long period of time, ball moss can grow so thick that it inhibits leaf production. Basically ball moss blocks leaves from forming, so the tree then has a limited amount of foliage that it is relying on, which in turn means less food for the tree. Aside from that, ball moss causes no damage or harm to your tree, other than it being unsightly.
The best course of action with ball moss is to have it taken out of the tree when you have your regular maintenance pruning done. This should typically be done every couple of years, just depending on what species of tree you have. By simply removing dead limbs in the tree, you’ll get quite a bit of the ball moss out (usually 60-70%). If that isn’t enough for you, then talk to your arborist and let him/her know that you’d like as much of it taken out as possible. Just keep in mind that ball moss is not killing your tree and in 90% of cases, there is no action needed aside from regular maintenance.
Bradford pear trees have become a popular addition to the urban landscape. Although the Bradford pear is a hardy tree consistently producing showy flowers in the spring and some fall color, the tree is not without its fair share of problems. The trees have a relatively short life span due to structural integrity issues, they are susceptible to a few disease issues and they can be overbearing on landscapes with limited space.
The average life expectancy of a Bradford pear is about 15 years. While the tree is capable of producing viable foliage for more than 15 years, this is typically how long the tree will last before it begins to fall apart. The numerous branches that originate at a central point cause structural defects that lead to the splitting apart of the tree (see pic). Pruning the tree to promote more upright growth and installing cables and braces to support weak joints can add to the life of the tree. In some cases, with regular maintenance and inspections, a bradford pear may last 20 or even 25 years.
For the most part, Bradford pears are highly resistant to disease and insects. There aren’t any know major insect problems and only two disease that commonly get into Bradford pears: fire blight and bacterial leaf scorch. 
Both diseases are treatable. Fire blight needs to be caught early to prevent significant damage. In fire blight the disease starts at twig ends and progresses back toward the main stem. The dead foliage will be a very dark brown and remain attached to the tree. In bacterial leaf scorch the leaves will turn a light color brown and fall from the tree similarly to normal leaf drop.
Bradford pears can be a good landscape plant if you are looking for a temporary (short lived) tree and there is adequate room for growth (need minimum of 10-15′ in all directions). In small spaces the pear can be overbearing as they grow very quickly and block virtually all sun when full grown. They also produce large amounts of surface roots so they shouldn’t be planted where lawn/soil surface needs to be smooth such as high traffic areas or near concrete patios that may be broken by the tree roots.
I'm Keith Brown, owner of Austin Tree Experts. This is my repository of tree knowledge. I hope you find what you are looking for. Let me know if you don't.
