Extension News

Ask the ISU Experts

Note to media editors:

Got gardening questions? Contact the Hortline at (515) 294-3108 (Monday-Friday; 10 a.m.-12 Noon and 1-4:30 p.m.) or send an e-mail to hortline@iastate.edu. For more gardening information visit us at Yard and Garden Online at www.yardandgarden.extension.iastate.edu.


The berries in my grape clusters are not ripening evenly. Why?
Several factors could be responsible for the uneven ripening of the berries within a cluster. Possible causes are over-cropping (too many grape clusters on the vine), a potassium deficiency, moisture stress or 2,4-D damage. 

Over-cropping is the most common cause for home gardeners. An average grapevine may have 200 to 300 buds, which are capable of producing fruit. If grapevines are not pruned properly in late winter, the number of fruit clusters may be excessive. The vine is unable to ripen the large crop properly, resulting in uneven ripening of the berries within the clusters. In Iowa, the maximum number of buds that should remain on a grapevine after pruning is 60. 

When would be a good time to move an 8-foot-tall spruce with a tree spade? 
Early spring (before bud break) is the best time to transplant evergreens. Evergreens can also be transplanted in late summer (late August through September). Evergreens transplanted after September may not have adequate time to reestablish themselves in the landscape before the onset of winter and are susceptible to winter injury. 

When can I divide my lungworts? 
Lungworts (Pulmonaria spp.) can be divided in late summer/early fall or after flowering in spring. Carefully dig up the entire clump, divide the clump into sections with a sharp knife. Each section should contain several leaves and a portion of the root system. Replant immediately. 

My trumpet vine is growing vigorously, but isn’t blooming.  Why? 
The trumpet vine (Campsis radicans) is a woody vine that produces orange to reddish, trumpet-shaped flowers. After planting, trumpet vines often don’t bloom for 3 to 5 years. The trumpet vine has to grow and mature before it is capable of flowering. There is nothing that can be done to force the vine to flower. Eventually, the trumpet vine will bloom. 


Contacts :

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

Jean McGuire, Extension Communications and Marketing, (515) 294-7033, jmcguire@iastate.edu