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. -  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 can I propagate a grapevine? 

While grapevines can be propagated by several methods, they are most commonly propagated by taking hardwood cuttings. Hardwood cuttings are made from the dormant canes of the preceding year’s growth. Cutting material should be collected in late winter.


Home gardeners pruning their grapevines in March can make cuttings from the pruned material. Grape cuttings should be approximately pencil-size in thickness and 12 inches long. When making the cuttings, the bottom cut should be just below the lowest bud while the upper cut should be 1 to 2 inches above the top bud. 


After making the cuttings, loosely tie them in a bundle. Place the cuttings in a plastic bag with some lightly moistened peat moss, then store in a cool location, such as a refrigerator or garage.  As soon as the soil is workable in spring, remove the grape cuttings from cold storage. Set the cuttings in the ground vertically with only the top bud just above the soil surface. 


What are the differences between the various types of sweet corn? 

Standard (su), supersweet (sh2), and sugar-enhanced (se) are the three major types of sweet corn.  They differ in sweetness, keeping quality and seed vigor. 


Standard sweet corn varieties possess the traditional sweet corn flavor and texture. Unfortunately, the ears of standard sweet corn varieties retain their quality for only one or two days in the garden. Also, standard sweet corn varieties don’t store well as the sugar is quickly converted to starch. 


Supersweet or shrunken-2 sweet corn contains up to twice the amount of sugar as standard varieties. (The common name shrunken-2 is derived from the shrunken or wrinkled appearance of the dry kernels.) Also, the conversion of sugar to starch occurs at a much slower rate. As a result, supersweet varieties may be harvested and stored over a longer time period.


Supersweet varieties, however, do have some drawbacks. Yields of supersweet varieties are generally lower than standard sweet corn. Also, the seeds of shrunken-2 varieties are smaller than standard sweet corn varieties and germinate poorly in cold soils. While standard sweet corn can be planted in late April in central Iowa, supersweet varieties should not be planted until mid-May. 


The sugar levels of sugar-enhanced sweet corn are between those of standard and supersweet varieties. The soft kernel pericarps make sugar-enhanced sweet corn tender and easy to chew.  The harvest and storage periods of sugar-enhanced varieties are slightly longer than standard sweet corn. It’s generally recommended that sugar-enhanced varieties be planted one week later than standard varieties. 


The newest type of sweet corn combines some of the characteristics of supersweet and sugar-enhanced sweet corn and is referred to as synergistic sweet corn. Synergistic varieties have higher levels of sugar than sugar-enhanced sweet corn. Their kernels are more tender than supersweet varieties. Synergistic varieties should be planted later than standard varieties as their seeds germinate poorly in cold soils. 


When should I start caladiums indoors? 

Plant caladiums indoors four to six weeks before the average last frost in your area. Tubers should be planted 1 to 2 inches deep. When planting tubers, place the knobby side up.  The knobs are the tuber’s eyes or buds. 



Contacts :

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

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