SEPTEMBER
2002

 

 

 

By
Beverly Shaw
 
Advanced
Master Gardener
Purdue University

 

 

 

 

 

9-05-02

Question and Answer

Q. I love red geraniums. I would like to know how one might start plants, and when you would start them. Also, what is the best plant food to use to grow beautiful geraniums? -- Tom Schmitt

A. The two main methods of propagating geraniums are by cuttings or seeds. Cuttings usually are taken from outdoor geraniums in late summer or early fall. Cut off 3-4-inch shoots, and remove the leaves on the lower part of the stem. A rooting hormone, available at most garden centers, can stimulate root production. Dip the bottom of the cutting in the powder, and shake off the excess. Then, stick the cuttings in a rooting medium of coarse sand or a mixture of coarse sand and sphagnum peat moss (1:1 by volume). A flower pot or wooden container that holds 3-4 inches of rooting medium and has bottom drainage holes is sufficient. To allow air movement and prevent the rapid spread of disease, separate the cuttings so that they do not touch each other. Water the cuttings thoroughly. Cover the container and its contents with a plastic bag, and place in a brightly lit location, but out of direct sunlight. It is better to keep the cuttings and rooting medium somewhat dry to decrease the chance of disease. Roots should develop in 3-4 weeks. After the cuttings have rooted, place each in a separate pot in good-quality potting soil without plastic covering, and set in a well-lit, spot such as a south window. The plants can be overwintered this way, then set out next year in your garden.

The other method of propagation is from seed. Geranium seed is readily available at garden centers and in mail-order catalogs. Sow seeds indoors 12-16 weeks before last frost, maintaining a temperature within the medium of 75° F during germination, which takes 5-15 days.

Bedding geraniums are sun lovers that perform best in a rich, well-drained, loamy soil. Geraniums are considered heavy-feeders, meaning they demand frequent supplemental fertilization in order to keep their foliage dark green and continuously blooming. A garden fertilizer with a N-P-K analysis of 5-10-5 or 6-12-12 applied at a rate of 2 to 3 pounds per 100 square feet (one heaping teaspoonful per square foot) is recommended before planting. Through the growing season, geraniums require fertilization every 4 to 6 weeks. Apply 10-10-10 or 8-8-8 at the rate of 2 pounds per 100 square feet. Choose a fertilizer with a slow-release form of nitrogen to guard against leaching of nitrogen during heavy rains, which may damage ground and surface water quality, and to ensure a steady supply of nitrogen to the growing plants.

Q. I recently purchased a clematis, and it is entwined around a wire arch. Since planting it about three weeks ago, it now seems to be dying, despite faithful watering and attention. Is it possible that the wire is causing this? Should I have removed the wire prior to planting? -- Karen Patchett

A. Clematis vines are usually woody at the base and incredibly easy to break. The wire arch provides support for the vine and some protection for the stem. It may be left in place at the time of planting. During transportation or planting, the stem may have been partially broken, causing the leaves to slowly wilt. Inspect the base for any damage.

Alternatively, the death of the plant could be related to the site. Make sure that you are not overwatering. Water deeply once or twice a week, allowing the soil to dry slightly between waterings. Once the plant is established, you can reduce the watering schedule. Soggy soil kills many newly installed plants. There's no way to know if the plant needs water without checking the soil moisture. The best way to do this is by feeling the soil with your fingers. Mulch or the soil surface can look amazingly dry, even when the soil is waterlogged 3 inches down!

Finally, it's possible something is wrong with the soil itself. Sometimes, but rarely, a planting site was previously an area where a substance was spilled or sawdust piled from a construction project. When you plant the replacement, consider a different spot, if you suspect the site is detrimental to the plant. If not, amend the soil with compost or other organic matter to provide the best home possible for the next clematis.

Now, for the good news! It's possible the clematis is suffering from transplant shock and may not actually be dying. Dieback of some leaves or branches sometimes occurs when plants are installed. For more information on transplant shock, go to http://www.extension.purdue.edu/extmedia/BP/BP-31.html.

Q. How do you get rid of purslane? It doesn't do any good to till it in because the pieces take root, and it just grows again. If you could let me know how to get rid of it, I would appreciate it. Thanks. -- Matt Johnson

A. Purslane thrives in hot, dry weather. The green, rubbery leaves are one-half to 1.5 inches long on thick, reddish-green stems. It sometimes bears yellow flowers, and the seeds are borne in a small pod with a top that comes off like a lid on a cookie jar.

Chemically, you can treat with glyphosate (sold as Round-up or Kleen-up) but you must use care. Any green plant material sprayed with glyphosate is killed, so spraying with this non-selective herbicide is not recommended anywhere near desired plants, such as vegetables or flowers.

Or you can pull them out by hand. Since purslane roots wherever it touches the ground, any plants that are pulled or hoed must be completely removed from the garden, or they'll root again! Instead of reducing the population, hoeing can increase it. A layer of mulch at least 3 inches thick will help reduce weed populations from garden beds. Purslane is a warm-season annual, so weed removal, mulch and a pre-emergent herbicide can prevent the same problem from reoccurring next year. If you're directly seeding new vegetables or flowers in the garden, do not use a pre-emergent herbicide, as it will keep those plants from germinating.

On the up side, purslane is an excellent crunchy salad plant. Check out http://aggie-horticulture.tamu.edu/plantanswers/98promotions/april/recipes.html for a host of recipes for stems and leaves, including Purslane Con Queso, Pickled Purslane, and Ham and Purslane on Rye. Another Web site with loads of information is http://www.hort.purdue.edu/newcrop/1492/neglected.html#Purslane. Here, you'll find ways to increase production (if you just can't get enough of it), as well as interesting purslane facts.

 

Q. I just buried my last acorn squash plant, the lone survivor of four others and four zucchinis. The plants lost color, then suddenly wilted and died. I could not find any cause for most of the plants, but the last plant had several white larvae in the stem.

Were the other plants also parasitized, and I just didn't find the grubs, or are these symptoms indicative of several plant problems? If this is a typical squash infestation, how do I prevent the loss of my plants? Is there a way to treat this after the plants develop symptoms? -- Rebecca A. Schmeltzer

A. The white larva is a squash vine borer and, typically, large portions of the plant die off at a time. The way to avoid larvae is by preventing the adults from laying eggs there. This begins in June and continues for four to six weeks. During this time, you can protect the plants with a floating row cover over them, but it must be removed to allow insects to pollinate the flowers. Unfortunately, it's difficult to allow the pollinators in and keep the vine borers out! Alternatively, you can wrap nylon stockings or aluminum foil around the stems, or inspect and remove eggs as they're discovered.

Plant a second planting in mid summer, after the hatch period is over for another chance at harvesting zucchini. Select an early-maturing variety, and hope for a late frost in the fall. You can also plant a very early crop of Hubbard squash to act as a trap crop.

Chemically, insecticides should be applied from the middle of June and reapplied every seven to 10 days for four to six weeks. Make sure you target the stems. Carbaryl (Sevin) is labeled for borer control in gardens. Or try the new products containing permethrin or esfenvalerate as an active ingredient. They have good residual activity and may give you the best control.

If your plants are attacked, remove the borer and cover the vines with moist soil at the leaf joints to encourage secondary roots that can support the plant. At the end of the season, make sure all plant debris is removed from the garden. To destroy overwintering cocoons, till the soil in the fall or spring.

 

Contact: B. Rosie Lerner
Editor: Olivia Maddox,