Ask the Experts

EMERALD ARBORVITAE LIMITATIONS

Question: I have a row of Emerald Arborvitae screening my patio. They are perfect for this spot and have been in the ground for over five years. Back in July several rapidly turned brown and died. Why did they die as they were established?

Answer: Emerald Arborvitae fills an evergreen niche. Growing about 3 feet wide and 10-12 feet tall, it fits nicely in tight spaces. While this plant fits many locations, it does have its limitations. The challenge is it has a very shallow root system and does not tolerate drought conditions. The combination of dry soils and heat are even more deadly. This is the combination we experienced in July.

The best recommendation for this plant is to never consider it established. Water even during temporary drought conditions. This could be during the heat of summer or even dry winter conditions. The tree gives no warning it is in distress and declining, it just turns brown and dies. Other tips for success include reducing competition from grass, and to use mulch to keep the soil cooler and help retain moisture.

CALADIUMS IN FULL SUN AND SHADE

Question: I noticed in your demonstration garden located at the Extension office you have caladiums growing in full sun. I thought they were shade loving plants.

Answer: Caladiums can take full shade to sun. Recently I had the opportunity to tour the Lake Placid, Florida area, where about 99% of the world caladium supply is grown. Their fields were in the blazing hot summer sun.

Caladiums can develop either shade or sun tolerant leaves. Plants grown in the shade and moved to the sun will burn, but new sun Emerald Arborvitae struggle with dry soil and heat. Some druplets can turn brown or white from summer heat. Heart-to-Heart Lemon Blush caladium

tolerant leaves will develop. The other key to growing in the sun is even soil moisture is required. Caladiums will not take dry soils. Be brave and try this colorful foliage plant in just about any location. They can put on quite a show in a sunny area.

DOES TROPICAL MILKWEED ACTUALLY HELP MONARCH BUTTERFLY

Question: I was saddened to see our monarch butterfly placed on the endangered list. I have planted several milkweeds in my garden but have shied away from the tropical as a friend told me it can spread a disease to monarchs. I want to do all I can to help so what is your take on tropical milkweed?

Answer: The potential issue with tropical milkweed is a protozoan parasite, Ophryocystis elektroscirrha or OE for short. OE levels can build up in the milkweed and adversely affect the growth and development of monarchs.

The issue with OE tends to be a more of a problem in temperate climates where the tropical milkweed does not die back, becoming perennial. In climates where tropical milkweed is an annual, like the KC area, the risk is lower. The Xerces Society recommends cutting the tropical milkweed back a couple of times during the growing season to reduce the spread. This is difficult to do if you have eggs or caterpillars.

The other concern with tropical milkweed is it does help delay the migration in the fall since a late food source is available. Xerces says to remove it in the fall, again, this is difficult to do. What does this all this mean? My take might not be embraced by all. Plant tropical milkweed, treat it as an annual, and do your part to help the monarchs.

CLARIFY THE NEED TO OVERSEED LAWN

Question: Do I really need to overseed my yard every fall? Some companies make it sound like it is an annual practice like fertilization.

Answer: Your goal in caring for a lawn is to never need to overseed. Overseeding a lawn is only necessary if you have patches that have died due to summer stress and other factors. If you have a good stand, maybe a little thin in areas, fertilization in September and November will probably help the lawn thicken up and fill in on its own. Assess your lawn and only seed if necessary.

BLACKBERRY FRUIT DAMAGE CAUSES

Question: My blackberries had a heavy set of big berries. When I started to pick there were partially brown berries and some of them had an off flavor. What caused these brown spots in the berries and how can I prevent them?

Answer: A blackberry is a composite of many tiny berries called druplets. Some of these druplets can turn brown or white when ready to pick. There are a couple of reasons for the off color. One is stink bug damage. Their feeding can damage the berries. The other and most likely cause this summer was the broiling hot summer sun. When temperatures climb to over 90 degrees the sun can burn or scald the individual druplets. The sun cooks the berries. Damage from either can impact the flavor.

Since most blackberries ripen during the heat of summer this can be difficult to control. Provide good soil moisture, enough leaf canopy to help shade the plants, or put up a shade structure reducing the sun rays on the developing fruits.

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.