Extension News

Ask the ISU Experts

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 e-mail us at hortline@iastate.edu. For more gardening information, visit us at Yard and Garden Online, http://www.yardandgarden.extension.iastate.edu


I recently purchased a Norfolk Island pine.  How do I care for it? 


The Norfolk Island pine is a popular houseplant. During the holiday season, many individuals turn their plants into living Christmas trees by decorating them with miniature lights, ribbons and ornaments. The Norfolk Island pine thrives indoors when given good, consistent care. Place the Norfolk Island pine in a brightly lit location near an east, west or south window. Rotate the plant weekly to prevent the plant from growing toward the light and becoming lopsided. 


Thoroughly water the Norfolk Island pine when the soil surface becomes dry to the touch. Discard the excess water, which drains out the bottom of the pot. From spring to early fall, fertilize the plant with a dilute fertilizer solution every 2 to 4 weeks. A temperature of 55 to 70  degrees F is suitable for the Norfolk Island pine. Winter is often a difficult time because of low relative humidity levels in most homes. Raise the humidity level around the Norfolk Island pine with a humidifier or place the plant on a pebble tray. Low relative humidity levels, insufficient light, or infrequent watering may induce browning of branch tips and lead to the loss of the lower branches. 


Which trees and shrubs provide food for birds during the winter months? 


When attempting to attract birds to the landscape, trees and shrubs that provide food during the winter months are extremely important as natural foods are most limited at this time of year. Trees that provide food for birds in winter include hackberry (Celtis occidentalis), hawthorn (Crataegus species), eastern red cedar (Juniperus virginiana) and crabapple (Malus species). Shrubs that provide food for birds include red chokeberry (Aronia arbutifolia), northern bayberry (Myrica pensylvanica), sumac (Rhus species), roses (native species and Rosa rugosa), snowberry (Symphoricarpos species), nannyberry (Viburnum lentago) and American cranberrybush viburnum (Viburnum trilobum).  


What are some good gift ideas for gardeners? 


Garden calendars are excellent gifts for gardeners. The 2006 Garden Calendar from Iowa State University Extension contains attractive photographs and monthly how-to tips in a 9 x 12-inch format. The calendar also includes a list of ISU horticulture publications and the addresses of local county extension offices. The ISU Garden Calendar is available for $8 at local ISU Extension county offices and for $8 plus postage from the ISU Extension Distribution Center at www.extension.iastate.edu/store. Other garden calendars can be purchased at local bookstores and other retail businesses. 


All gardeners can use an additional book to add to their library. Excellent reference books include “Growing Perennials in Cold Climates” by Mike Heger and John Whitman; “Growing Shrubs and Small Trees in Cold Climates” by Nancy Rose, Don Selinger, and John Whitman; “Manual of Woody Landscape Plants” by Michael Dirr; “Herbaceous Perennial Plants” by Allan Armitage, and many others. 


Plants are always great gifts for gardeners. Possibilities include the poinsettia, Christmas cactus, Norfolk Island pine, cyclamen and other seasonal plants. An amaryllis bulb is another popular gift. A gift certificate from a local garden center and nursery would also be greatly appreciated. The gardener can use the gift certificate to purchase a tree, shrub or other plants next spring. 


An individual or family membership to the Des Moines Botanic Center, Reiman Gardens at Iowa State University, Iowa Arboretum or other public garden is sure to delight your gardening relatives and friends. An annual membership gives them free, unlimited visits for one year and other benefits. 


Other possibilities include tools, clothing, and garden accessories (bird feeder, fountain, garden statuary, weather instruments).You might even consider a garden gnome. The possibilities are almost endless. 


Contacts :

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

Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

There are no photos for this week's column.