Extension News

Ask the ISU Extension Gardening Experts

Note to media editors: Got gardening questions? Contact the Iowa State University Extension 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.


How do I care for garden geraniums? 

Garden geraniums (Pelargonium x hortorum) are attractive flowering plants for beds, borders, containers, hanging baskets and window boxes. Geraniums are easy to grow and provide color in the garden from May to frost. 


Flowers are available in red, pink, salmon, orange, white, lavender and bi-colors. Several fancy-leaf geraniums possess silver, white, gold, red or purple markings on their leaves. 


Geraniums should be planted outdoors when the danger of frost is past. Generally, mid-May is a safe planting time for geraniums in central Iowa. Geraniums perform best in fertile, well-drained soils in full sun. Plants will grow in partial shade, but will not bloom well.


For optimum flowering, geraniums should receive at least eight hours of sun. Geraniums also respond well to applications of fertilizer. Prior to planting, apply and incorporate 1 to 2 pounds of an all-purpose garden fertilizer, such as 10-10-10, per 100 square feet of garden area.


Geraniums growing in containers should be fertilized approximately every two weeks with a water soluble fertilizer. During dry periods, a deep soaking once a week is sufficient for plants in beds and borders, while plants in containers will require more frequent watering. Water geraniums in containers when the soil surface becomes dry to the touch. 


If possible, avoid overhead watering as wet foliage encourages disease development. To keep plants blooming continuously throughout the summer, remove spent flowers on a regular basis. Deadheading prevents seed development and encourages the plants to produce additional blooms.  It also improves plant appearance. 


I just planted some blueberries. When can I expect them to produce a crop? 

Blueberry plants should not be allowed to bear fruit the first two years after planting. Any blossoms that form should be removed. Removal of the flowers will maximize vegetative growth and increase yields in later years. Blueberry plants should come into full production by the fifth or sixth year. 


I can’t get grass to grow under a large maple tree.  What are my options? 

Most turfgrasses have a difficult time growing in the vicinity of large shade trees. If your efforts to grow turfgrass are unsuccessful, there are alternatives. Areas around and beneath trees can be mulched with wood chips or shredded bark.


Planting a shade tolerant groundcover in the area is another possibility. Shade tolerant groundcovers include bugleweed (Ajuga reptans), wild ginger (Asarum spp.), barrenwort (Epimedium spp.), sweet woodruff (Galium odoratum), hosta (Hosta spp.), and spotted deadnettle (Lamium maculatum). 


Contacts :

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

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