Garden Detective: Protecting fruit from squirrels

DEAR JESSICA: I thought there was something wrong with my peach tree (a disease or a nutrient problem) because peaches, just beginning to ripen, have been falling to the ground at a rate of more than 30 a day. Then yesterday I saw a pair of squirrels jump from the ground to the branches, take a peach, nibble on it and then come back for another. At this rate there won't be any peaches left for us (something we experienced last year). Is there something I can do to scare them off? I'm not interested in harming them. Thank you for any information you can provide. -- Dan Cully, Patchogue

DEAR DAN: I feel your pain: My pear tree has been stripped bare by squirrels. I watch helplessly from my window as they climb a branch, swipe a pear, take a bite and abandon it for another, like a toddler with a box of chocolates.

Although there are repellents on the market, I wouldn't use any on edibles. Capsaicin, the spicy compound in hot peppers, has been shown to deter squirrels, but it may penetrate your peaches' thin skin and alter the flavor of the fruit. Still, it might be worth a try.

Depending on the size of the tree, you can cover it with netting. If that isn't practical, you might install a motion-sensored sprinkler, like the Havahart Spray Away (which I'm experimenting with to keep my dog out of my perennial beds).

Speaking of my dog, I trained her to stay off the couch by covering the seating surface with slightly crumpled aluminum foil sheets, on the advice of a friend. It worked (for a while), so I was inspired to wrap the pear trunk with foil last year, and it did seem to deter the squirrels, until a windy storm blew it all away. Tape likely would have avoided that mishap -- and family cooperation likely would have kept the dog off the couch.

DEAR JESSICA: I am writing to you for an elderly friend who is unfamiliar with computers and email but who frequently quotes from your advice column. She has a recipe for controlling mildew that you mentioned in one of your columns. One of the ingredients is horticultural oil. She has visited several local nurseries and has had no luck locating the oil. Do you know where she could find it? She lives in Stony Brook. I know she'd be thrilled with whatever personal advice or suggestions you could offer. -- Pat Urquhart, Stony Brook

DEAR PAT: So nice of you to help out your friend. Indeed, powdery mildew can be controlled by spraying plants with a tablespoon each of baking soda and ultrafine horticultural oil diluted in a gallon of water. Horticultural oil should be available at most large nurseries and garden centers, as well as at big-box stores like Home Depot and Lowe's. But if your friend is having difficulty finding it, it is likely sold out and will not be reordered until next year, which is typical for seasonal supplies. Perhaps you could place an order for your friend at Amazon.com or Gardeners.com, both of which had products in stock at the time of this writing.

DEAR JESSICA: You helped me when some of my arborvitae looked as if they were on their last legs. We sprayed them, and they are beautiful and so very green and healthy. So I hope you can help me with my impatiens. I always thought they were the easiest plants to grow. The area that I have them in is sunny until about 3 p.m. I planted healthy plants in May, but they just don't grow. In fact, they shrink. They are still alive, but half the size they were when first planted despite being watered regularly. I just can't imagine what is wrong with them. I hope you will be able to help. -- Karen Vati, Massapequa Park

DEAR KAREN: Although there is a fungus that can infect and stunt impatiens, and a plague called downy mildew, which has been a problem recently and causes yellowing of leaves and loss of foliage, you don't mention any other symptoms, so I'm assuming your plants are small but not displaying signs of disease. From your description, it sounds like your impatiens are simply getting too much sun. Impatiens are shade lovers -- unless you have the New Guinea type, which can tolerate more sun. At this point, I'm not sure they'd survive a move, but you can try. Otherwise, water every day and try fertilizing a bit, then pick a shadier spot next year.

DEAR JESSICA: Help! I bought three astilbe plants last month. They're getting plenty of water and about three hours of afternoon direct sun. Any clue as to why the flowers are dying and the leaves are curling up? Do you think I can save them? Should I have waited until the fall? -- Linda Curro, Jericho

DEAR LINDA: I think the direct sun is your problem. Astilbe are shade plants that can tolerate partial sun but do best in part shade. They also require frequent watering. If during the heat wave you weren't watering deeply and often (at least once a day, especially since they were new plantings), that definitely would explain curling leaves. There's also a chance they have leaf curl disease (are the leaves spotted?), but given the weather around the time you planted them, my guess is the sun and watering.

LI TOMATO CHALLENGE

Emma Pnini, 6 1/2, of Roslyn is at it again. Last year, the adorable novice gardener tried her hand at tomatoes and entered the Great Long Island Tomato Challenge. This year, with some experience under her belt, she added snap peas, string beans and lettuce to her garden. We'll see you in August, Emma!

Are you in? The 2012 Great Long Island Tomato Challenge will be held at 7 p.m. Friday, Aug. 24, at Newsday, 235 Pinelawn Rd., Melville. Bring your biggest, heaviest ripe tomato to the event, where I will weigh it and name this year's Tomato King or Queen. In the meantime, send a photo of yourself with your plants and a note about your growing methods to me at jessica.damiano@newsday.com, and you might be featured next.