Extension News

Ask the ISU Experts

Note to media editors:

Got gardening questions? Contact the Hortline at (515) 294-3108 (M-F; 10-12 & 1-4:30) 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


Last summer the leaves on my peach tree were puckered and reddish in color.  What was the problem?


The symptoms are those of peach leaf curl.  Peach leaf curl is a fungal disease.  The disease is caused by the fungus Taphrina deformans.  Infections occur as the peach tree buds begin to swell in spring. 


A single fungicide application will control peach leaf curl.  Fungicides, such as lime sulfur, Bordeaux mixture or chlorothalonil, should be applied in fall after leaf drop or in late March before the buds begin to swell.  To achieve control, all branches and twigs must be thoroughly sprayed. 


I would like to move a small tree in the yard.  How should I proceed? 


The best times to transplant deciduous trees are early spring before growth begins or in the fall after leaf drop. Evergreens are most successfully transplanted in early spring and late summer (late August and September). 


To minimize damage and improve their chance of survival, dig and move trees with balls of soil adhering to portions of their root systems. The soil should be moist when the plant is dug. If the soil is dry, thoroughly water the area 3 to 4 days before digging. 


When digging trees, the radius of the root ball should be approximately 8 to 12 inches for each inch of trunk diameter at chest height.  For example, a tree with a 1-inch-diameter trunk should have a soil ball that is 16 to 24 inches in diameter. Using a spade, dig a trench around the tree to a depth of 1.5 to 2 feet. 


Then cut beneath the roots, rounding the bottom of the soil ball.  Tip the soil ball to one side, place a piece of burlap in the trench on the opposite side, then carefully tip or roll the soil ball over onto the burlap. Tightly wrap the burlap around the soil ball and secure the burlap with twine. Lift and carry the root ball rather than grasping the trunk. 


If possible, replant the tree immediately. Dig a hole that is 2 to 3 times the width of the tree’s root ball. The depth of the hole should be about 1 inch less than the height of the soil ball.  Carefully lower the tree into the hole, position it correctly, and begin to place soil back into the hole. Firm the soil around the tree’s root ball with your hands. When the hole is about two-thirds full, cut and remove the twine around the soil ball.  Also, cut away the exposed portion of burlap. Then complete the backfilling of the hole and water thoroughly. 


Do not allow the soil ball to break during the digging, moving and replanting process. Home gardeners should limit themselves to transplanting small trees. Trees with a trunk diameter greater than 2 inches should be left to nursery professionals. 


When should I fertilize my raspberries? 


Fertilize established raspberries in early spring before new growth begins. Apply 4 to 5 pounds of 10-10-10 or a similar analysis fertilizer per 100-foot row. Uniformly broadcast the fertilizer in a 2-foot band.  If the raspberries are mulched with sawdust, wood chips or corn cobs, apply a slightly heavier rate of fertilizer. Specific fertilizer recommendations for your garden can be obtained by conducting a soil test. 


Manure may be substituted for chemical fertilizers. Apply 50 to 100 pounds of barnyard manure (cow, hog or horse) per 100-foot row. 


Do not fertilize raspberries in late spring or summer. Late spring or summer fertilization encourages succulent, late season growth. Late season growth is susceptible to winter damage.



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.