University of Maryland Extension: Ask the Plant and Pest Professor


September 20 release from the University of Maryland Extension on garden and pest questions.

Question #1:Looks like grubs have destroyed a section of my lawn this summer. What do I do now and what should I do to avoid the

Lady fern (Athyrium filix-femina)

problem next year?

Answer#1: First of all check to make sure that the area actually has grubs. Your lawn could have died from drought. Grub damage is not evident until the end of summer through fall. To check for grubs dig up a square foot section of the damaged area. It is normal to find some grubs but unless you are seeing about 6-10 grubs in that area the grass died for another reason. If grubs are the culprit prevent problems next year by applying a grub control product that contains either acelepryn or imidacloprid in June through mid-July. To repair the lawn now, rake the area to remove dead grass and as many of the grubs as you can and reseed with tall fescue seed. See publication HG 78 The Japanese Beetle found on our website for more information on grub control and also HG 102 Lawn Establishment, Renovation and Overseeding for tips on repairing your lawn.

Question #2: This has been another disappointing year for my lima beans. For the past 2 years, I have planted Dr. Martin lima beans with little success. The vines looked very healthy and blossomed all summer, but did not produce pods or if the formed they quickly dropped from the vine. Can you shed some light on what is going on? I have been growing limas for years now.

Answer #2: We have been contacted by many homeowners this past summer with the same concern as yours. There are many contributing factors to the poor performance of lima beans: weather, lack of pollinators, and in some areas stink bug activity. It has been determined that stink bugs like to feed on lima beans. They usually damage the beans as they develop in the pod but some people think that stink bugs may actually be feeding on the flowers in the early part of the season. Certainly our summers have become hotter the in the past few years. We had record breaking temperatures for a significant portion of the summer. Anytime that we get daytime temps in the 90’s and evening temperatures in the 60’s or above for several days the plants grow well, but drop flowers and small pods. Actually smaller seeded Carolina or Sieva types are more heat tolerant than Dr. Martin or King of the Garden large-seeded types. Bush types may also be better suited. Changing what you plant next season certainly is worth trying.

Question #3: Recently I cleared a small section in the woods on my property of invasive weeds. I am looking for information on native perennials that would do well in the shade with little care. They also have to be deer resistant. Do you have any ideas?

Answer #3: After clearing an area of invasive plants it is important to cover the ground as soon as possible to prevent regrowth. Planting shade loving perennials will take time to fill in, so in the meantime cover the area with leaves or mulch. There are many native perennials for you to consider. Native ferns such as lady fern (Athyrium filix-femina), leatherwood fern (Dryopteris marginalis), and Christmas fern (Polystichum acrostichoides) are excellent choices. Allegheny spurge (Pachysandra procumbens), Jacob’s ladder (Polemonium), foam flower (Tiarella), and the shrub fothergilla, which can handle partial shade, are plants to consider. Even though these plants are supposedly deer resistant you should still spray them with a deer repellent for at least the first year after they are planted.

“Ask the Plant and Pest Professor” is compiled from phone and email questions asked the Home and Garden Information Center (HGIC), part of University of Maryland Extension, an educational outreach of the University of Maryland. To ask a home gardening or pest control question or for other help, go to www.hgic.umd.edu. Or phone HGIC at 1-800-342-2507, Monday through Friday, 8 a.m. to 1 p.m. Follow us on Facebook and Twitter.

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