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Ask Dr. Hort: Establishing and caring for Knock Out roses

Controlling fleas outside is difficult

Q: My daughter lives in Seminole and is having trouble finding a pesticide to kill fleas in the yard without harming the dog or the grass. The back yard has a tall wooden fence around it. Our terrier is pretty much limited to that area and the house. She does not have contact with other animals. We have tried giving her baths with flea soap and used Frontline and some pills the vet gave us. All these work for a few days, then the fleas are back. The only place I can think she is getting fleas is the back yard; we have not noticed any in the house.

Is there a pesticide spray or something that won't harm pets or the plants?

Paul Krusee, St. Pete Beach

A: Controlling fleas outside is not easy as the fleas are at different stages of development, making it hard to kill them all at once. Your best bet is to hire a pest control company that will make the required repeated visits. If you choose to do it yourself, you will need a good dial-mix hose-end sprayer, a professional-strength insecticide such as Permethrin Pro or Dragnet and an insect growth regulator, or IGR, such as Nylar. Remove pet toys, food and water dishes and other items before treatment. Mix pesticides in the sprayer based on label instructions. Use sweeping motions to equally distribute the solution on the entire lawn. You will need at least 3 gallons of solution per 1,000 square feet. Keep people and pets off all treated areas until dry. Repeat the application in two weeks and continue to monitor.

Establishing, caring for Knock Out roses

Q: I have several Knock Out roses and unfortunately I planted them in the full sun (west and south exposure). They really struggled this summer, but they seem to be coming around now that the weather is a little cooler. I may put up one of those car canopies next year to offer some shade. Do you think that would help or will it be a waste of money? I really have nowhere else to put them. What do you suggest as far as a fertilizing schedule and what type should I use, and when and how do I prune them and to what degree?

Susan Weiland, Seminole

A: Knock Out roses are a great addition to any landscape, especially where gardeners want roses without the level of maintenance that many hybrids require. Knock Outs arrived on the scene a decade ago from plant breeder Bill Radler. His seven or eight hybrids are now the largest-selling group of roses in North America. They were bred to be drought-tolerant, resistant to several fungus diseases such as black spot, easy to maintain and bloom profusely, and so far they have lived up to expectations. Your location is perfect, six to eight hours of full sun or scattered shade. Low-flow irrigation is best for establishment, and I think this is what tripped you up. Create a soil saucer 6 inches high around the drip line of the plant and fill it with water every other day. Begin tapering off after three weeks to twice per week, then just water as needed through the winter and by spring they should be fully established. Even though Knock Outs are drought-tolerant, they need additional water through the establishment period (two to four months for a 1-gallon-size plant). Fertilize with bonemeal, bloodmeal, green sand — organically — or a commercial rose fertilizer, three times per year in between bloom cycles. Prune to maintain your desired shape before you fertilize. Sit back and enjoy in 2011.

Slow-growing wax plant striking in bloom

Q: A friend has this plant she started from a leaf given to her about eight years ago. It has thrived in her kitchen window but only bloomed once. Is this a type of orchid? I'm going to try to start another plant from some leaves she gave me, which appear somewhat fleshy. Any hints on care and feeding? Thank you.

Nancy Everett, Homosassa

A: The pictures that you sent me are the hoya, or wax plant, Hoya carnosa. There are many species and many leaf forms with several variegation designs. It belongs to the Asclepiadaceae family along with butterfly milkweed. Wax plant is unique in that it blooms from the same spur every time.

With each bloom more buds are set, and after many bloom cycles a complete ball of blooms opens with a sweet, almost dainty fragrance. It's a beautiful sight. With the name wax plant, both the leaves and the flowers look, well, fake.

It will grow as an epiphyte (air plant) as do many orchids and bromeliads. Take a cutting with two sets of leaves and stick in a small pot of soil, water sparingly, place in a part sun location and fertilize monthly with a soluble product.

It is very slow-growing, so after propagating it may take up to a year or more to set its first bloom spur. Be patient, as more and more bloom spurs set, it is absolutely striking.

Skunk vine is hard weed to control

Q: Recently I heard someone on the radio mention Fusilade herbicide for skunk vine control. I have not been able to find anyone who has used it for this smelly weed, which can really get out of control. What is your advice, other than pulling it out by the roots, which I've done a lot in years past.

Sonya Ziegler

A: Of all of the weeds out there, you have been invaded by one of the toughest to control. While researching any possible controls for skunk vine, Paederia foetida, I ran across this amusing explanation of your situation in an Institute of Food and Agricultural Sciences publication.

"If you're plagued with this stuff, you'll go through stages: fiercely attacking it, admiring your progress, fiercely attacking it, admiring your progress, fiercely attacking it, grumbling in frustration, fiercely attacking it, grumbling more and louder, fiercely attacking it, astonished that you could feel such vehemence against a plant, fiercely attacking it, wanting to cry."

Does that sound like what you have been going through? Fusilade, the herbicide that you mentioned, is a selective herbicide that kills grasses only. Brush-B-Gone or Brush Killer both contain triclopyr, which is pretty successful in controlling skunk vine. But you do have to be careful in and around your landscape plantings. Spray when the vine first sprouts and keep on top of it. Read the pesticide label and spray in a small area before broadcast spraying. Good luck!

Stale beer attracts slugs, snails

Q: Do you have any home remedies for getting rid of slugs and snails? Katherine Moore

A: Are you sure slugs and snails are the problem? They both like moist or wet areas. Is it feasible to eliminate such areas? If not, bury some straight-sided cans so the lip is even with the soil, and fill each half full with stale beer. They are attracted, fall in and can't escape. What a way to go!

You can also take an aluminum pie tin, cut maybe four or five entry slots (about 1-inch square), pour some dry dog or cat food in a little pile and place the tin over the food. The next morning, scoop up slugs and snails and discard in the garbage in a closed container.

There are also some eco-friendly baits with iron phosphate, like Sluggo or Escar-go. Sprinkle bait in area of concern. They are attracted to the bait, eat it and are dead in days. What's left breaks down into fertilizer elements and is harmless to pets, toddlers or beneficial earthworms. Now, sit back with the nonstale beer and watch!

Need help? Dr. Hort (Greg Charles) answers questions about landscape problems. E-mail him at or mail questions to HomeLink, Features Department, St. Petersburg Times, P.O. Box 1121, St. Petersburg, FL 33731. Describe problem in full, and include your name, city of residence and contact information. If possible, include a good-quality photo. Fuzzy ones won't do. Photos cannot be returned.

Need help? Enter Greg "Dr. Hort" Charles, who for more than 30 years educated gardeners through the Pinellas Technical Education Centers. He answers questions about landscape and garden pests.

E-mail your questions to or to (put Dr. Hort in the subject line). Mail questions to HomeLink, Features Department, St. Petersburg Times, P.O. Box 1121, St. Petersburg, FL 33731. Describe your problem in full, and include your name and contact information. If possible, include a photo. We will print his advice on Saturdays in HomeLink.

Ask Dr. Hort: Establishing and caring for Knock Out roses 11/26/10 [Last modified: Friday, November 26, 2010 3:30am]
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