Q: I lost four Indian hawthorns last year to cold weather. I liked them and would like to replace. Any advice? — Steve Dunn, email
A: Different varieties of Indian hawthorn seem to have different reactions to cold and different susceptibility to leaf spot. According to plant experts, 'Blueberry Muffin', 'Snow', 'Eskimo', 'Georgia Charm', 'Georgia Petite' and 'Eleanor Tabor' are very cold-hardy. I have a list of Indian hawthorns that are disease resistant at bit.ly/GAhawthorn.
Q: Could you advise me where I can purchase horticultural oil? Or is this something I can make myself? — Fran Wheeler
A: Horticultural oil is a specially refined oil that suffocates insects without hurting your plants. I discourage you from making it yourself. Cooking oils and automotive oil will not control insects. Most nurseries carry some sort of oil product for insect control. This is a great time to use horticultural oil to control scale insects.
Q: Is it too cold for Roundup to kill the weeds now growing in my flower beds? — James Diffly, Cumming
A: The leaves on the weeds you aim to control should be actively photosynthesizing when glyphosate (Roundup, etc.) is applied. That means the air temperature should be above 50 degrees. You may get some control at lower temperatures, so experiment by spraying the weeds on a sunny day and see what happens. In cold weather, don't expect results for two weeks.
Q: My granddaughter came across an odd looking, dark brown "bowl" of loose "dust" in my dormant Bermuda lawn. I found online that it's a mushroom labeled Scleroderma geaster. Is this something that will eventually eat up the grass? — Alberta Lucas, Fayetteville
A: I believe you two found an earthstar. This particular mushroom, like most, is very dependent on particular environmental conditions to show itself. The spores are all about us, but only a certain sequence of temperature, moisture and a suitable host will trigger its eruption. It feeds on decaying plant material, like dead tree roots or lawn thatch. You can't do much about them other than dig up the ones you see. More may pop up next fall or you may not see others for years.
Q: I just moved to southeast Georgia and the soil in my backyard is pretty much the consistency of beach sand. Should I apply some type of top soil before planting sod? — Dan Hay, Camden County
A: I think that any soil conditioner you add will be a plus for the sod. Sandy soil drains quickly after rainfall or irrigation. You have to really be observant to know when to water when the weather is hot. Tilling soil conditioner into the soil first is like adding an underground water reservoir, allowing the grass to go longer between waterings. Go online to find a company that delivers soil conditioner in your part of the state. Measure the lawn area before you call them so you can calculate how much material will be needed.
