Neil Sperry's Mailbag

DEAR NEIL: What would keep a 2-year-old crinum lily from blooming? We have them 15 to 18 inches apart and the middle one has bloomed several times but not the other two.

That's difficult to diagnose without seeing them, however I will say that that is pretty close for most crinums. They tend to grow large. Maybe the middle one has better placement in terms of light and moisture. Try replanting the other two this fall. Even if you just move them 12 or 18 inches farther away it will give you the chance to redo their planting soil at the same time.



DEAR NEIL: How can I eliminate crabgrass in my lawn? I've had a small patch of it in the past but this year it is rampant. Why would there be so much now?

Crabgrass is an annual grassy weed. It germinates in early spring, grows and begins producing seed by early summer and continues until frost. Just to be sure we're talking about the same grass, it is light-to-medium green in color. It produces short runners to 8 to 12 inches long. The seed heads are borne above the grass and they somewhat resemble helicopter rotors. If that's what you're seeing it probably got a toehold during the drought and has flourished with this year's rains. Prevent its germination by applying pre-emergent herbicide granules a week or so before your average last killing freeze date and again 3 months later. You can eliminate existing crabgrass and other grasses in bermuda turf by spraying with MSMA. Do not use MSMA in other types of grasses as it will kill them.



DEAR NEIL: A year before my beloved stepfather died he gave me a mulberry tree seedling from Marietta, GA. My mother made heavenly jam from its parent tree. My tree is now 8 years old and has never produced a single fruit. Will it ever do so? I have it growing at the edge of a woodland. It has grown well, but I am so hopeful to have fruit.

Be patient. It's not uncommon for fruit trees that have been grown from seed to take that long to start producing. They invest most of their early years simply in growing to their mature size and form. If you think about it, animals operate about the same way. One of the next several springs it will start producing and it will never stop again. I have yet to see a seedling mulberry tree that didn't eventually have fruit. Of course, it will grow best in full or nearly full sunlight. Hopefully your woodland won't be an issue.



DEAR NEIL: You created a stir in our house with your comments that this year's heavy rains have depleted our soils of nitrogen. Doesn't lightning add nitrogen back to the soil?

Plants require many nutrients to grow vigorously and remain healthy. None is used in greater quantity than nitrogen. Whether it's from organic or inorganic sources, nitrogen eventually becomes water-soluble. In fact, that's the way plants take it into their root systems - in water solution.

When heavy rains come they leach much of that available nitrogen out of the plants' root zones. We can plant legumes with their nitrogen-fixing bacteria, and thunderstorms do have some effect, but the elephant's share of the work comes from the regular addition of nitrogen fertilizers.



DEAR NEIL: I recently read about using NAA (naphthalene acetic acid) on crape myrtle sprouts at the base of the bush to control sprout regrowth. Do you have any experience with this chemical and procedure for crape myrtles? If so, where would I obtain NAA and what would be the directions for its use?

The University of Georgia's Center for Urban Agriculture has the most conspicuous mention of this I could find online. To my knowledge it is not a common practice beyond research horticulture. On a practical note experts say that if you leave a very short portion (1/4-inch) of the branch collar of the side shoots when you remove them the plant will stop producing additional sprouts within a year or two. I have observed the same thing with my own crape myrtles for many years - if I remove the suckers by pruning for the first couple of years most of the work will then be behind me.



DEAR NEIL: My dinner-plate-sized dahlias bloomed well but are now leggy. If I cut them back will they bloom again this fall?

It is little short of a miracle that they bloomed in the first place. Large dahlias are very poorly suited to Texas conditions. They need to be grown where summer temperatures are 15 to 25 degrees cooler. My guess would be that your plants will be weakened so much that they won't regrow. However, they do need to be trimmed following flowering.



DEAR NEIL: When do we trim oleanders? Mine have gotten really leggy.

Immediately after their main late-spring bloom. It's not too late, but you'll want to do so immediately. Do as little pruning as you can to lessen chance of soft new growth and subsequent freeze damage.

Neil Sperry
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