Esperanzas might have succumbed to the winter

Published 5:25 am Thursday, March 29, 2018

Dear Neil: My Gold Star Esperanzas may have frozen this past winter. I have yet to see any green growth. I cut the tops back to the ground and still have them mulched in pecan leaves. Should I give up on them?

A: It’s not looking good for them. Normally winter-hardy in the southern third of the state and occasionally farther north, Esperanzas were really hurt by the extended and repeated cold this past winter. It does vary from one city to the next and site by site, but if you don’t see new growth emerging soon you’d better think about replacing them.

SELECTIVELY PRUNE

Dear Neil: I have a row of nandinas beneath some of our windows. I’ve tried to trim them evenly, but the ones on the ends are really scraggly and mostly stalks. Should I trim them back to the ground or do something else?

A: Your photo shows plants that vary a lot in their vigor. If these were mine, I would selectively prune the tallest canes back to the ground, probably one-third to one-half of the total number of canes. They will send out new sprouts from below, and those will fill in the growth. You must never trim nandinas part way up their stems. They will try to branch there, and that will leave you with really odd-looking plants. Apply an all-nitrogen fertilizer immediately after you trim them and water them deeply to encourage vigorous regrowth. In all honesty, this would have been better if you had done it six weeks ago, before any of the new spring growth had begun. Aim to do so earlier next year.

NITROGEN

Dear Neil: I’m planning to fertilize my St. Augustine beneath my live oaks around May 1, as per your recommendations (I believe). What fertilizer would you suggest?

A: Most tests on Texas soils show that we need to add only nitrogen, not only to our lawns, but also to trees, shrubs and even flowers and vegetables — that most soils accumulate phosphorus to excessive amounts. In the absence of a current soil test, that would probably be my suggestion. Half or more of that should be in slow-release form. Mid-April would be a good time for the first feeding, with a second feeding coming early June and a third and final fertilization in early September. I normally don’t recommend feeding St. Augustine in July and August since nitrogen promotes gray leaf spot fungus which is active at that time.

BRADFORD PEARS

Dear Neil: The white pear trees that were in beautiful bloom a few weeks ago were gorgeous. Are they good landscaping trees?

No. Most are Bradford pears. They are brittle, narrow-branched and weak-wooded, usually splitting down the middle after 10 or 15 years. Adding to that, the rootstock, Callery pear, sets fruit and the seeds germinate in wetter parts of the state, making it invasive in those regions. As pretty as they are, there are much better trees.

Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or email him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.