It is encouraging to see how many landscaped plants are returning. Given the extreme temperatures we experienced during the February frost, it could have been a lot worse. Despite some losses, many plants recover, albeit at their own pace. Bottle brushes are growing new from the ground, Indian hawthorn trees are showing green in the battle for dead branches, the pride of Barbados (a slowpoke compared to others) is finally making its way over the mulch and a good number of figs are showing very few side effects from that Freeze. Then we have native fruit trees like Texas Persimmon (Diospyros texana) and Mexican plum (Prunus Mexicana) that have reddened, bloomed, and borne fruit as if they were saying, “Freeze what freeze?”
Q: How big or old does a bougainvillea have to be in the ground to flower? Can I help you?
A: If it’s a newly planted bougainvillea, it can take a few years for it to bloom. So patience is the best advice. They can be grown in containers or in the ground, so size doesn’t matter. Make sure it gets at least 6 hours of sunlight and stays dry but doesn’t wither. Do not over water and do not fertilize until it starts to bloom. They’d rather be forgotten unless we get too hot and dry. One day it will surprise you when you almost forget you planted it. Bougainvilleas affected by freezing can have fewer flowers for up to two years. As an aside, the beautiful color we enjoy from this plant is its paper-like leaves called bracts. The actual flower is small and cream-colored.
Q: My Japanese tulip tree (pink magnolia) is 40 years old and has not recovered from the frost. It was in full bloom, and now the dead blossoms are just hanging on it. It has shoots near the bottom of the trunk, but nothing over 18 inches. Is there hope? Should I cut it back all the way?
A: We see this type of response in many trees. The top growth / branches have not recovered, but new growth is emerging along the trunk at the base of the tree. You need to decide whether to remove the tree or prune it to a point where the new growth can continue to grow and develop. Let the new shoots establish this season, then thin them out in the fall, removing the weaker stems.
Q: I have three red oak trees and two peeled beautifully after freezing. The third has no leaves, but has sprouts on the trunk that move up and along the lower third of the tree. Is there any hope that this tree will peel off?
A: This is a great example of the interaction between genetics and environmental conditions. Your red oaks are seed propagated, so they have different parents. The two trees that have peeled off are from parents who are more cold tolerant than the third tree. It is a good sign that shoots are appearing on the trunk. At least they know the tree is alive. If new growth does not appear in the upper canopy, this tree is not catching up with the others and has a different shape / appearance. With the right pruning and time, you can still have a great shade tree.
Q: My pink magnolia, which is 40 years old and quite large (up to the roof of my two-story house), has not recovered from the frost. It was in full bloom and beautiful, but now the dead flowers are just hanging all over it. It erased a few leaves in some places near the top, but they withered and died. There are some shoots that expand at the bottom of the stems, but nothing above about 18 inches in height. Is there hope? Should I look for living branches that are as tall as possible to see if they are green? Should it be trimmed? Please give me advice on what to do at this stage.
A: It is good news that there is growth so you know that all is not lost. Plants deal with the stress of freezing in different ways, and some take longer. Unsurprisingly, it peeled off and then died, as it can take weeks for frost damage to appear. You can wait a little longer to see if new growth occurs higher than what you observed. Otherwise, it will seem like the tree is showing you where it lives. Anything above the new growth can be removed once you are sure it isn’t flushed out elsewhere. On the positive side, the beautiful flowers are back at eye level for better admiration.
Q: Should Torenia bloom all the time or will it bloom in waves? Do I have to play it dead?
A: Torenia Fournieri, like most annuals, should flower evenly unless it is in too much shade or a fertilizer with too much nitrogen has been applied. Even with even blooms, there may be times when the bloom load fluctuates, but bloom should not stop completely. Deadheading isn’t required for flowering, but it helps pushing them back while they are small to create a fuller plant.
Q: After freezing, I cut off all the mushy leaves from my amaryllis and they immediately sent out new green shoots and bloomed beautifully. Now some of the leaves are yellowing and developing red spots that spread. What should I do?
A: It looks like your amaryllis (Hippeastrum) may be affected by a fungal disease called red spot (Stagonospora curtisii). It matches your description of the red spots that keep growing and eventually the leaves turn yellow. It’s a difficult condition to treat, but you can check into a fungicide product that has amaryllis or onions on the label. The worst scenario is that you have to pull them up when the lightbulbs are colored red. Proven prevention methods include not watering the leaves and avoiding too much shade.
Q: Our bottle brush was about 15 feet high and had a huge canopy that our lawn crew cut to about 3 feet high. After cutting open the limbs, they cut the rest to the ground. Do you think it will come back If not, my husband wants to grind the stump. We have three smaller ones that are sprouting.
A: Bottle brushes have taken it really hard this year. Although new growth is expected out of sheer desperation, you can wait until the end of May. Some plants just take longer than others after such a shock, but ultimately it’s hard to guess which plants will survive and which will not. It really depends on how long you want to wait … or not wait!
Q: My Sandankwa Viburnum hedge is slowly coming back from the roots. How long could it take to get a high (7 foot) privacy hedge back?
A: The Sandankwa viburnum (Viburnum suspendensum) is a popular evergreen shrub native to Japan. The rate of growth depends on moisture, fertility, and the amount of sunlight it receives. Within 2-3 years, it should produce enough growth to look like it did before freezing.
Brandi Keller and Paul Winski are Harris County horticultural agents at Texas A&M AgriLife Extension.
