Readers seek help for stressed trees, failed flowers
Q: We live on 6.5 acres and have lost about a dozen oak trees in the past year. I don’t know why. Bark just falls off their trunks. I see small holes in the wood of the trunks. One Texas A&M Extension agent said it might be Hypoxylon canker, but no one ever looked at them to confirm it. At 80, I’m unable to cut them. I’ll just have to let them fall. What fast-growing tree could I plant for shade on the west side of my house where these trees once stood?
A: There are many things we need to cover.
First, I wish I knew what type of oaks you have. That would make answering your questions much easier. Second, and equally important, you do not want a fast-growing shade tree. Every last one of them has some fatal flaw that will limit its life expectancy to 10-20 years. In the meantime, their upkeep causes significant management problems, so I suggest you avoid them at all costs. Go for quality instead.
As for the holes in the bark/ trunks, that sounds like some species of borers, such as redheaded wood borers. They typically move into trees that are in serious stress. I’ve even seen them show up as trees were being bulldozed. Hypoxylon canker is another problem that shows up once a tree is being seriously challenged, perhaps by drought or damage from extreme cold. We saw a huge amount of it in Texas’ post oak forests in the years following the
biblical drought of 2011.
Texas A&M has information on Hypoxylon canker on the university website, but for some reason you must now register to download it (free) from their bookstore. There is a short and good write-up on the fungus at the Oklahoma State University website. (https://extension. okstate.edu/programs/digitaldiagnostics/plant-diseases/ hypoxylon-canker-on-oaks.html) The OSU website has very good photographs to help you identify it, and they suggest getting infected trees cut and removed as soon as possible to remove sources of infection that could help it spread to other trees nearby.
Q: Last summer this tree was just fine. This spring it was very slow to produce leaves. I have fed it. This is how it currently looks. Can you tell me what is going on with it?
A:
I believe you have an ash tree, and it looks like it is loaded with ash seeds. They produce
clusters of “winged” seeds — the wings aid in the dispersal of the seeds. The past two winters did a lot of damage to ash trees across Texas, and now the survivors are facing an even worse fate. Emerald ash borers, insect pests that have literally ruined entire ash forests in the Midwest and Northeast, have made their way into Texas.
I won’t suggest that your tree has been hit (yet), but everything points to their covering Texas with their awful damage. I can’t tell much from the photo, so my best suggestion is that you contact a certified arborist in your vicinity to work with you on this tree. Your county Extension office should be able to help you find one. You can also check the website of the International Society of Arboriculture. They have a “find a certified arborist” tool on the site using your ZIP code.
Q: I bought and planted this “perennial” to replace one that died after the past two winters. Should I deadhead the old flowers? Will it bloom again this year? In fact, what is it?
A:
This is one of the largerflowering types of gloriosa daisies (close relatives of our wildflower black-eyed Susans). I can’t be more specific from your photo. There are many varieties sold in the nursery marketplace. Some are really just annuals and fold up tent after their initial round of spring and early summer blooms. Those types generally have larger leaves (much like the one you have).
I suspect this one will not flower again. I suggest you try a variety called Goldsturm. Although its flowers are smaller, they’re produced by the dozens for 10 weeks or longer each late spring and early summer. The plants are decidedly perennial.
Q: I read with interest a column you wrote back in 2012 about marigold trials at the Dallas Arboretum. Transplants that I have set out in the fall have always failed. They eventually get spider mites and die. Plus, I can’t find the varieties you mentioned back then. Are those varieties good over the entire state?
A:
The takeaway I learned from the research of my friends at Texas A&M, notably Steve George and Jerry Parsons, also Greg Grant, as well as the folks at the Dallas Arboretum, was that you must start with transplants that are showing color, but not yet in full bloom. When nurseries choose plants from growers, they often opt for plants that are in full bloom because they know they will sell more quickly. Color sells!
As for the best current variety, Steve Huddleston, recently retired from the Forth Worth Botanic Garden, has been using Taishan Orange and Taishan Gold in many of his landscapes. Hopefully you’ll be able to find those transplants in Texas nurseries in the next couple of weeks.