Garden columnist Dan Gill answers questions from readers each week. To submit a question, email Gill at [email protected]
I have a large mature water oak tree growing in my yard that worries me. There is a large cavity in the trunk. I don’t know if I should fill this with something like concrete. Also, I saw signs that the tree is infested with termites. I love this tree, but if it falls, it would be a disaster. I have to decide what to do with this tree before hurricane season arrives. —Laura Fredrickson
First, you must contact a licensed arborist to come professionally assess the tree. A list of licensed arborists by parish is available on the Louisiana Department of Agriculture and Forestry website. Use this list to ensure that you are selecting licensed businesses and individuals. I’m glad you’re doing this now. Everyone should inspect their big trees for problems now, before hurricane season.
There are a few main considerations when evaluating a tree for possible removal.
THE SPECIES: Some tree species are more dangerous than others. Unfortunately, large and old water oaks are susceptible to falling in hurricanes. These are the oaks with the shortest lifespan, usually only living 60 to 80 years. When they reach the end of their life, the trunks usually rot and tend to break and fall in strong winds. So the species, size and age of your tree are cause for concern and may mean that removal should be considered.
THE STATE OF THE TREE: Large and old water oaks very often have rotten trunks, even if there are no outward signs and the tree looks healthy. If cavities or decayed areas are observed, this confirms the rotting state of the trunk. The presence of fungi growing from the trunk can also indicate the presence of internal rot.
A termite infestation in the tree is another bad sign. Termites do not eat rotten wood; they eat solid wood. So your tree has a fungal rot that rots the trunk wood and termites eat away the solid wood. Together they weaken the trunk and make the tree more likely to fall in a storm, and removal should be considered.
WHAT WILL IT HIT IF IT FALLS? : If a tree with significant problems does not hit or damage any significant structure if it falls, you have the option to leave it. If it could crush a house or pose a hazard to people in the event of a fall, its removal should be considered.
When planting different colors of amaryllis together in a bed, a friend told me that over time all the amaryllis would turn the same color. Is it true? If so, how can I plant the amaryllis of different colors to make sure they won’t change color? —Christine Palmer
What they say is that if, for example, you plant a red amaryllis next to a white amaryllis, the red amaryllis will cause the white amaryllis to start producing red flowers (or the red becomes white). It will not happen. The color of the flowers produced by a plant is determined by its genes. A plant cannot change its genetic makeup just because it grows near the same type of plant with different characteristics.
Over time, it is possible for one or more of the colors to die out or be crowded out by more vigorous types. Also, if the seeds are allowed to ripen and fall to the ground, the offspring may be different colors and may crowd out the parents (this can be avoided by not allowing the seeds to form). In these cases, it may appear that the colors of the flowers have changed over time, but that is not what actually happened.
BASIL TIME: Plant basil seedlings now and enjoy a wonderful fresh seasoning for summer cooking. Many herbs already in your garden, such as thyme, sage, oregano, mint, dill, cilantro and parsley, are at their peak of productivity over the next couple of months and will grow to as the weather warms up. Harvest freely and dry or freeze the extras.
BULB CARE: Remove spent flowers and developing seed pods from spring-flowering bulbs that need to be saved for blooming next year. Do not remove any green foliage. Wait until the foliage turns mostly yellow before pruning. The bulbs that reliably bloom again here do not need to be dug up and can be left in the ground.
Bulbs that rebloom well in our area include leucojum, many narcissus and daffodils, Dutch iris, amaryllis, ground orchid (Bletilla), Easter lily, bluebell, freesia, flower (Ipheion), hyacinths (will bloom again but the spikes are much smaller), Louisiana irises, spider lilies (Hymenocallis) and calla lilies (Zantedeschia aethiopica).
Many other bulbs, such as tulips, crocuses, anemones, squills and grape hyacinths will bloom rarely or produce inferior blooms next year, and can be picked up and discarded when they have finished blooming.
FERTILIZE NOW: Established perennials should be fertilized this month if you haven’t already. Use a general-purpose granular fertilizer or organic fertilizer dispersed evenly throughout the bed following package directions. After applying the fertilizer, water the bed by hand to remove the fertilizer granules from the foliage and down to the soil.
VINE PRUNING: Keep ornamental vines under control with regular pruning and training or they will quickly spiral out of control. If a vine is grown for its flowers, the heaviest pruning should be done after its main flowering period.