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


I would like to add some color to the winter landscape.  Which trees and shrubs have colorful fruit in winter? 


The drab winter landscape can be brightened with crabapples that possess colorful, persistent fruit.  ‘David,’ ‘Donald Wyman,’ Red Jewel®, and Sugar Tyme® have attractive red fruit.  ‘Adirondack,’ ‘Indian Magic’ and ‘Professor Sprenger’ have orange-red fruit, while ‘Canary,’ Golden Raindrops® and Harvest Gold® have yellow to gold crabapples. 


Two hawthorns noted for their excellent fruit display are the Washington hawthorn (Crataegus phaenopyrum) and Winter King hawthorn (Crataegus viridis ‘Winter King’).  The small, crabapple-like fruit of the hawthorns turns red in fall and persists into winter. 


Shrubs that possess attractive fruit during the winter months include the American cranberrybush viburnum (Viburnum trilobum), red chokeberry (Aronia arbutifolia)  and the Meserve hybrid hollies (Ilex x meserveae). All of the aforementioned shrubs have bright red fruit.  Snowberries and coralberries (Symphoricarpos spp.) have white, pink or purplish red fruit. 


What are the brown growths in my ash tree? 

The brown growths in your ash tree are probably ash flower galls. Galls are abnormal plant growths caused by insects, mites or other organisms. On ash trees, a tiny mite causes the male flowers to develop into roundish, green, 1-inch growths. In late summer/early fall, the growths turn dark brown and become woody. 


While ash flower galls are unsightly, they do not seriously harm healthy trees. Control treatments are usually not practical or necessary. 


How can I raise the relative humidity indoors for my houseplants? 

Many houseplants prefer a relative humidity of 40 to 50 percent. Unfortunately, the humidity level in many homes during the winter months may be only 10 to 20 percent. Humidifiers are an excellent way to increase the relative humidity in the home. Simple cultural practices also can increase the relative humidity around houseplants.  Grouping plants together is an easy way to raise the humidity level. The water evaporating from the potting soil, plus water lost through the plant foliage, will increase the relative humidity in the vicinity of the houseplants. Another method is to place houseplants on trays (saucers) filled with pea gravel or pebbles. Add water to the trays, but keep the bottoms of the pots above the water line.  The evaporation of water from the trays increases the relative humidity. 


Misting houseplants is not an effective way to raise the relative humidity. Plant foliage dries quickly after misting. Misting would have to be done several times a day to be effective and is not practical for most people. 



Contacts :

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

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

There is one photo available for this week's column.

Crabapple10-11-06, 1.2 MB