Ask the Experts

CHALKY FILM ON PEONY FOLIAGE

Question: The last few summers my peonies have not looked great. They get what I have been told is powdery mildew, a chalky grayish white film on the foliage. I read on Facebook that I should cut my plants back in the summer to rid the plants of this issue. Is this the best solution?

Answer: NO! Never cut peonies back in the summer. Don’t remove the foliage until it browns naturally in the late summer or fall. Peonies need the green foliage growth to help produce energy for next year’s bloom. Cutting back early in the season robs the plant of any chance of generating food reserves. I shudder every time I see this recommendation on social media. It is just bad advice!

One recommended option to fight mildew and other diseases is sanitation, but that alone cannot eliminate the mildew. Mildew happens when we have cool, wet springs. Cutting back in the fall is ideal to remove the infected foliage. Your options are either to live with the issue or spray multiple fungicide applications early when the growth begins. I roll with the punches and don’t spray. So far even with the whitish foliage I have not seen a reduction in flowering.

BEE FRIENDLY WITH MICROCLOVER

Question: I want to plant a lower maintenance and more bee friendly lawn. One option I read about is microclover. Is this a good alternative to bluegrass or tall fescue?

Answer: Lawn care is changing as more people look for lower maintenance and environmentally friendly options. There is not a simple solution. Microclover is related to the white clover commonly found in our lawns. As the name implies, microclover is more compact, and has a lower growing habit. This potentially makes it a Newly seeded microclover Deer damage

good ground cover alternative to traditional lawns.

A monoculture or pure stand of microclover is probably not the answer. It is not well adapted to thrive in heat and drought. It will dieback during the seasonal temperature extremes and leave bare spots of open soil. Microclover, or maybe better yet white clover, probably works best when seeded into a bluegrass or tall fescue lawn. This mix can reduce fertilizer, water and mowing needs while still providing pollen for bees. This will also provide more consistent coverage of the soil to help reduce erosion and a muddy mess.

BEST BARRIERS FOR DEER AND RABBIT

Question: Last year my fruit trees got hammered in the winter by deer and rabbits. Is there a repellent I can spray on the trees to help protect them?

Answer: Deer and rabbit repellents are on the market, but I am not for sure I would rely on their effectiveness. They are short term and require multiple applications. Physical barriers are your best bet.

Rabbit damage can be controlled with a tree wrap. Use either plastic or heavy paper applied from the base of the tree up to a height of 18 to 24 inches. Deer are more of a challenge as their rutting severely damages the trunk. A wire ring, out and around the tree works best. Building a fence with concrete reinforcing wire and T post are effective. Cattle panels purchased at farm supply stores can also be bent in a circle to ring the tree.

Another fruit tree pest is voles. Voles are mouse-like animals that gnaw on the bark at the base. Remove grass out and around the trunk a few inches to reduce feeding. Tree wraps will also protect the tree.

TIPS FOR NOVEMBER LAWN FERTILIZATION

Question: My lawn survived the summer and now I want to fertilize one last time since Extension recommends November fertilization. I am getting conflicting information about what fertilizer to use. I hear I should use a fertilizer with high nitrogen and little or no phosphorus. I have also been told to use a fertilizer in November with phosphorus. What should I be applying?

Answer: November fertilization is the second most important application. It prepares the lawn for spring green up with less top growth. It also helps build strong roots and crowns.

Extension recommendation is to use high nitrogen and little or no phosphorus. There are several reasons for this recommendation. First, most local soils naturally have ample levels of phosphorus. Adding more does not improve growth. A simple Extension soil test measures soil pH and will provide this information. Second, overloading the soil with phosphorus leads to erosion and leaching, which will move the excess into streams and ponds. This can increase algae issues. The only time Extension will recommend a fertilizer with phosphorus is when you are seeding as research does show an application at this time will increase root development. Established lawns, unless a soil test indicates low levels, never need an application with phosphorus.

Stick with a fertilizer product analysis which has the first number (N=nitrogen) around 30% and the second and third numbers, (phosphorus=P and the potassium=K) as close to zero as possible. One last thought, grass cannot read so brand names are not as important as the nutrient analysis.

MULCH STRAWBERRIES IN WINTER

Question: I am growing strawberries for the first time. I have heard I should mulch for the winter. What does that mean?

Answer: Strawberries are very shallow rooted. Winter freezing and thawing can heave or push the plants out of the ground, which makes them susceptible to winterkill. Mulching for winter reduces this effect and helps delay spring growth, this also reduces flower bud damage from a late freeze.

The ideal mulch should be light and fluffy. Straw or leaves work best. Wait to apply until after several hard freezes into the 20s, and the plants are fully dormant. Cover the bed with 2 to 3 inches of mulch. The point of the mulch is not to keep the plants warm, but buffer them from the extremes of high and low temperature fluctuations. When spring arrives and growth begins, push the mulch off the plants and use as a summer mulch on the soil to help control weeds and conserve moisture.

DENNIS PATTON Horticulture Agent

Dennis Patton is the horticulture agent for Johnson County K-State Research and Extension. For free information fact sheets, visit www.johnson.ksu.edu, or call the Extension office at 913-715-7000.