DECEMBER
2010

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

12-2-10

Question and Answer


Q. For the last two years my Nandina has produced a lot of flowers that promised to berry, but the berries seem to drop off before fruition. It has berried beautifully in the past, and there has been no change in environment.

A. Nandina is marginally hardy to southern Indiana, but it is considered to be an invasive, weedy species in the southeastern United States where it forms vigorous spreading colonies. Although commonly called heavenly bamboo, it is not a bamboo but rather a member of the barberry family. There are quite a few cultivars in commerce that vary in plant size, foliage, flower and fruit color. Generally, the plant flowers in May or June and the fruits ripen in September or October. The individual flowers have both male and female parts present; however, fruit set is improved when there is more than one plant. Some cultivars have been selected for lack of fruiting in an effort to decrease invasiveness. But since your planting used to produce fruit, is it possible that you had more than one plant in the past? Also, pruning after flowering would remove the potential for fruit.

Q. During this past summer's drought, crabgrass took over much of my yard. Is there any effective, cheap way now to get rid of it, or has it already seeded itself for the spring? Now that it's almost winter and it has turned brown, would going out and manually pulling it up by the root do any good? What options do you recommend?

A. Crabgrass is an annual plant, meaning it only lives for one growing season. The plants flower and produce seed in July, then die at first frost. So there is not much point in pulling the plants out now. Unfortunately, crabgrass produces a lot of seed in summer that will then germinate next spring. Crabgrass is a really tough weed to completely eradicate, and it thrives in poor, sparse turf. The best strategy is to prevent the crabgrass as much as possible. Good lawn care practices, including appropriate fertilizing, watering and mowing, will help the turf grass be more competitive. A pre-emergence herbicide applied in early spring before the crabgrass germinates can substantially reduce the population next season. In central Indiana, you would need to apply by early April most years. For more information on crabgrass control in home lawns, see Purdue Agronomy publication AY-10-W at http://www.agry.purdue.edu/turf/pubs/AY-10.pdf.

Q, My Concord grapes used to get ripe all at the same time. Now, the last two years, they don't. They all get ripe so unevenly; some are green, some are ripe and some are over ripe or starting to rot on the same bunch of grapes. What is my problem?

A. Some grape-growers have experienced uneven ripening this year, particularly with their Concord grapes, and this seems to be an issue when the weather has been exceptionally warm. Some of the berries in the cluster remain sour, hard and green while others develop the purple color and soften during the ripening process. The green berries will be full-sized, but will not be sweet. For some reason, those berries never go through the increase in sugar and decrease in acids that commonly occurs during fruit ripening. It is not clearly understood why this phenomenon occurs, but hot weather is thought to be partly responsible. So let's hope for better weather next year.

 

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,