Dear Neil: I planted Dreamland zinnias a week ago. One day they were fine, and the next day they were dead with a mold all over them. What would have caused that?
A: Without a photo it’s difficult to tell. Dreamlands are normally very good. Powdery mildew is known to attack zinnias, but not so much Dreamlands. It would have looked like a dusting of sulfur. You might try some of the other types that have been bred for extra mildew resistance. I don’t know whether the soil might have been waterlogged after rains or heavy watering or what the problem could have been. Again, a photo would have helped.
Dear Neil: You can see in my photo that our ornamental pear is very close to our house and its roof. Also to that of our neighbors. I’m concerned that the branches will split and do damage. Should I have it cut down and removed before that all happens?
A: That’s a great question. If its shade is important to you, I guess you could have an arborist cable it so it would support its own branches. However, it probably only has a few more years before it will begin to develop some kind of problem down in that narrow crotch. Moisture and old bark and debris will catch there, causing a poor union. Plus, the branches on the left are just about to start rubbing against the edge of your roof, and that will cause major damage. It also could lean into the fence. I don’t sound like its strongest advocate, do I?
Dear Neil: How much attention must I pay to the quality of peat moss I apply to my St. Augustine lawn to help restore it after damage from take all root rot? I have a relatively average lot, but it’s going to require a lot of peat. Can I buy it in bulk instead of bags?
A: Phil Colbaugh, retired plant pathologist with the Texas Agricultural Experiment Station of Texas A&M, who first identified that workaround for this fungus, notified me earlier this spring that the fungicide Azoxystrobin has shown good results in actually stopping the fungus, not just slowing it down like the peat treatment has done. It is sold to consumers under the brand name of Scotts Disease-EX. Commercial lawn care services use it as Heritage. And as for the peat, you want to buy bales of sphagnum peat (not bags of domestic peat) if you opt to go that route. It may be sold in bulk, but usually not at the consumer level. It is dried and compressed tightly to reduce shipping cost. You want it because of its very low pH. Still, I think you’ll find the fungicide more effective at a much lower cost.
Dear Neil: My bluebonnet plants are covered with seeds. When should they be harvested for next year?
A: Not until they have turned brown and rattle. You’ll have several days to harvest them before the pods start to break open and disperse the seeds onto the ground. If they’re in an area where there is no grass or other vegetation growing you can just let them resow themselves, but if you have to harvest them and store them, keep them cool and dry before planting them in late August or very early September.
Dear Neil: I have two tree-like weeds that are coming up within my crape myrtle trees. Is there some kind of weedkiller I can use to kill the weeds without harming the crape myrtles? Please don’t tell me I have to dig out the roots of the weed trees. I don’t think I could do that.
A: Your photos, unfortunately, are thumbnails — very small images. I believe one is a hackberry seedling. I can’t make out the other. Cut both off weeds at the ground so that as they sprout out with new growth you’ll be able to paint a broadleafed weedkiller (containing 2,4-D) on at spraying strength using a foam rubber paintbrush. Do not get it on the crape myrtles’ stems, and do not allow volumes of it to soak into the soil. You should, however, coat the little stumps of the weed trees. It will be taken into the stumps and carried into the roots. You might have to treat a second time 4 to 6 weeks later.
Dear Neil: My Texas mountain laurel seems to be declining. I have attached photos from 2012 and this week. I don’t see any evidence of an insect eating the leaves. What could be causing this, and what can I do to save the tree?
A: Your photos are thumbnails, but I can see the big changes. Look at the trunk to see if there is any evidence of decay or a fungus. If you see splitting or a small bracket fungus conk growing out of it, that was probably the cause. I lost a trunk on my own mountain laurel to that fungus. It disfigured the tree so badly that I replaced it with another species. I honestly don’t think you can save your tree. I wish we could have worked with it years earlier before it got to this point.
Dear Neil: We’ve had a grapefruit tree outdoors in South Texas for seven years. This season we had 12 nice fruit that we harvested in February. But this year we’ve had no flowers so far. Normally it’s had blooms by now, and our other tree is in flower at this time. What might we expect?
A: My guess would be that the tree just over-taxed itself with the last crop and is rebuilding itself this year. Judging from your photo, it certainly looks healthy. Perhaps your tree that is blooming now will provide you some fruit this time around.
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at firstname.lastname@example.org.