Question: I have 3 Jackmani clematis on trellises close by in same area that have bloomed profusely for many years. However, the one in the middle has a problem every summer -- the leaves start to turn a mottled yellow early on. The other two are okay. I treat all three the same with fertilizer, etc. Any ideas? Could the soil in that area be a different PH perhaps, and if so, what to do about it?

My garden club took a tour of a beautiful garden today and the owner told us she had taken a course at the University of Maryland recently where she was told never to use hardwood mulch, only pine bark or pine needles. Or, preferably no mulch at all. Said the mulch releases manganese into the soil, and also extracts nitrogen from the soil. We have used tan bark mulch from Hollins for years now and have thought it was good for the soil. Any thoughts on this theory?

How do you keep parsley a deep green? Mine seems to turn a slightly yellow shade after awhile. Could it be in too much sun?

Thank you for all your advice over the years, both on the radio and through this medium. Everything I have purchased from you has done beautifully, and I recommend you to my friends.
 

Answer: On the clematis, treat the soil with iron sulphate and magnesium sulphate. If that doesn't improve next year's leaves, the clematis probably has a noncurable virus and should be replaced.

On the mulch, using no mulch at all leads to a huge weed problem. Mulch also helps prevent ground water from evaporating and it protects the roots from summer heat and winter cold. Mulch temporarily takes nitrogen from the soil as it breaks down. But most of the nitrogen requirement is in the early stages of decomposition, before you buy the mulch. Towards the very end of the decomposition, mulch actually releases nitrogen into the soil. If you fertilize regularly, you certainly need have no concerns about nitrogen deficiency at any stage. Pine needles make an excellent mulch, but they have the same nitrogen cycle as other mulches. Pine bark and oak (tan) bark also each have essentially the same nitrogen cycle, but oak bark has several other advantages: shreds nicer; lasts longer; doesn't support either termites or artillery fungus. In all my gardening experience, I have known only one instance of excess manganese in the soil and it wasn't from mulch. (Manganese is a required soil micro-nutrient).

Parsley prefers some shade and rich moist soil.

Question: Hi, I have a David Austin English rose 'Heritage', in the spring it has beautiful buds but most of them turn brown and never open. Do you have a clue to what is wrong with it?

Answer: I suspect you have insects called "flower thrips." Remove the affected flowers and put them in a closed plastic bag, then into the trash. Spray with Orthonex weekly until the situation rectifies itself. Flower thrips are not easily controlled. Next year, start your spray program earlier, when the flower buds are less than half size.

Question: We have ant hills around the house. I used to use Dursban and Diazon, but I can't find either product anymore. What do you recommend for ant control?

Answer: Dursban and Diazon have both been discontinued and are no longer available. I have had good luck controlling ants with a relatively gentle insecticide that contains Permethrin; the brand I use is Tiger's Super 10.

Question: I follow your lawn care program but this year my lawn has a bad case of fungus. I believe I have both red thread and brown patch. Other years I followed your recommendation and sprayed weekly at the first indication of fungus with Seaweed, which controlled the fungus. This year the fungus seems more aggressive and it appears to be getting ahead of my treatments. What do you suggest? A year ago, I bought Daconil 2787 fungicide just in case I needed it and never used it.

Answer: Daconil 2787 is no longer labeled for lawn fungus. If yours has the old label which covered lawn funguses and it was properly stored, it is okay to use.

If you need a new lawn fungicide this year, I suggest Cleary's 3336 or Bonide's Infuse.