Extension News

Ask the ISU Extension Garden Experts: Dividing Asters, Currants and Pruning Blueberries

Note to media editors: Got gardening questions? Call the Hortline at (515) 294-3108, Monday-Friday from 10 a.m. to noon and 1 to 4:30 p.m., or send an e-mail to hortline@iastate.edu. For more gardening information, visit us at Yard and Garden Online, http://www.yardandgarden.extension.iastate.edu


When is the best time to divide asters? 
Early spring is the best time to divide asters. Dig up plants in early spring just as new growth begins to appear. Divide each plant clump into sections with a sharp knife. Each division should contain several shoots and a portion of the root system. Replant the divisions immediately. Keep the newly divided asters well watered through spring and summer. 

Which currants perform well in Iowa? 
Red, white and black currants can be successfully grown in Iowa. Suggested varieties (cultivars), along with a brief description of each variety, are provided below. 

Red Currants
‘Red Lake’ was developed at the University of Minnesota. Plants produce large, dark red berries on long-stemmed clusters that are easy to pick. ‘Red Lake’ is a hardy, vigorous, upright shrub.  ‘Wilder’ originated in Indiana. Plants produce large clusters of bright red berries. The berries mature earlier than ‘Red Lake.’ 

White Currants
‘White Imperial’ produces medium to large berries. Fruit are white with a pink blush. Excellent flavor. Considered by some individuals to be the best tasting of all currants. ‘Primus’ produces medium to large berries. Fruit mature later than ‘White Imperial.’ Berries are white with a yellow cast. Plants are vigorous and compact. 

Black Currants
‘Consort’ was developed in Ottawa, Canada. Plants produce clusters of soft, black, medium-size berries that possess a sweet, musky flavor. ‘Consort’ is resistant to white pine blister rust.  ‘Ben Sarek’ is a compact shrub that produces large, flavorful berries. The fruit make excellent jams and jellies. ‘Ben Sarek’ is highly resistant to white pine blister rust. 

Most currant varieties are self-fruitful. It is not necessary to plant  two or more varieties for cross-pollination and fruit set. 

How do you prune blueberries? 
Blueberry plants are small to medium-size shrubs. Blueberry yields and fruit quality decline when blueberry shoots (stems) reach five years of age. In late winter/early spring, prune out any dead or diseased stems. Also, prune out stems that are five years old and older. Allow one to two new shoots to develop each year. 


Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Willy Klein, Extension Communications and External Relations, (515) 294-0662, wklein@iastate.edu