Ask A Gardener: Your Gardening Questions AnsweredBy Melody Rose (melody)
August 4, 2012
Sierra77 asks: As you can see from the picture, the blooms on one of my 'Magnus' coneflowers appear to be forming multiple tiny blooms. It looks similar to a hen-and-chicks succulent. These blooms show no tendency to turn color at all. So far, only one plant is exhibiting this trait. I believe this plant came back from the roots because seedlings that came up this year are a lot smaller than this plant. I have done nothing different regarding this plant from prior years. Has anyone else experienced this and does anyone know what causes it? If nothing else, it just proves you can't predict what will happen in the garden!
Melody answers: I'm afraid your images show what is known as 'aster yellows' or yellow aster disease. It is a microscopic organism known as phytoplasma, spread by leafhoppers and is quite infectious. Most people who find this in their gardens ultimately end up removing all of their coneflowers. While it isn't often fatal, plants remain distorted and unattractive. It quickly spreads via the leafhoppers to other plants in your garden. The best remedy is to remove all affected plants and surrounding weeds. Aster Yellows can infect a number of species, so it is best to practice good garden sanitation when you find it. Chemical control of leafhoppers is generally not very effective either.
newlygardening asks: I am in Zone 7, it's been a hot summer. I have been growing a tomato plant and carrots. The carrots are sprouting and the tomato plant is just starting to get some real tomatoes on it. But, I've wanted to plant hydrangeas, they are so beautiful. I was wondering it was too late in the summer to plant them? I know these are perennials so I would love to plant them this season so next summer they'll be coming back into bloom. But, I don't know what I would do with them during Winter. It's been an especially hot summer in the region that I'm in, so do you think because of the weather it will still be warm enough in August to plant some hydrangeas? If it's too late I'll just buy some potted ones and care for those for a while if I can't plant them.
Melody answers: Autumn is the perfect time to plant new shrubs. However, I'd wait until the temperatures were a bit cooler. Warm weather often does more harm than good when it comes to planting shrubs. I planted hydrangeas in early June of this year and it has been such a struggle to keep them alive through the blistering heat of this summer that I wish I'd waited until fall. In our zone, (you and I share similar climates) I would plant new shrubs from mid-September until mid-November. They will have plenty of time to establish root systems and settle in before winter arrives. Water well each week if you are experiencing drought conditions and mulch the base of the plants just before the worst of the winter hits. You should be rewarded next year by some stunning blooms!
portette asks: Do New England Asters bloom the first year they are planted?
Melody answers: If you transplanted small nursery-type plants then yes, you should have blooms. Some asters will even bloom the first year from seed, it depends on how long the growing season is. I planted some mail-order transplants from Bluestone Perennials this spring and they are just starting to bloom. Depending on where you are, asters will bloom on up into December, as most can stand light frosts. Asters are easy-care and attractive to bees and butterflies and make excellent choices for your garden. They are hardy, disease and drought resistant and love the sun. This image is of my asters that I planted this spring and they are just starting to bloom.I'm looking forward to enjoying them for many years.
trishaa46 asks: This was the first year that our two grape vines bore fruit. We have harvested four huge baskets off of these two vines. They are a pink blush grape called Candace. The grapes remained small, about as big as a garbanzo bean, but were extremely sweet. My question is, are grape clusters supposed to be thinned as we do our peaches? What can I do next year to increase the size of the grapes? We irrigate, mulch and fertilize.
Melody answers: Your instincts were good. Grape vines typically produce more clusters than they have the ability to support, so thinning reduces stress on the plant and allows it to produce better clusters. You should prune and fertilize your grapes in late fall or early spring (depending on where you live). By fertilizing before the flowers emerge, you are encouraging better fruiting. Right after flowering and when the grapes are first set is the best time to thin. Remove any small or mishapen clusters and thin according to the vine's age. An older, more mature vine can support more grape clusters than vines just starting to fruit. The actual number of clusters removed will depend on how many the plant produces and the weather conditions. You might check with your County Extension Agent. Since you are in Missouri, The University of Missouri is where your Extension Service is based, but each county will have an office. The agent for your county is an excellent source for gardening and agriculture information geared to your exact conditions.
mistinichole asks: My husband and I have bought alot of seeds to grow in our hothouse. But we come across 4 of them like the India Brain Tree,Dwarf Blueberry,Giant Strawberry,and Tame Red Grape all say on the package to cold stratify seeds in freezer for 30-60 days. We did not know what it ment so looked it up on the computer ans some say to do it, but most said do not... We have never heard of this and we think it would kill the seeds..So do we do this and how and why????? Thanks-Misti
Melody answers: Yes, stratification is an important part of seed germination for many species. The term 'stratify' means to mimic winter conditions, to let the seed know it is time to sprout. Not all seeds need stratifying, but those that do generally will not germinate without it. Some seeds even need double stratification to germinate. The redbud tree (Cercis canadensis) is one of those...it needs the effects of two winters before it can sprout. Stratification mimics the winter conditions for each species and some will properly stratify with only refrigerator storage. These are usually plants that grow in warmer climates. You'll need to research each type of seed that you have to see what type of climate they grow in, as that will make a difference on your stratification method. I couldn't find anything on the India Brain Tree anywhere, but if you give me a botanical name, I'll try to help you out. Botanical names are very important, since they identify a specific plant. Many plants share the same common name and we need to know exactly which seeds you have to help you effectively. Some plants require stratification in potting mix, while others are completely fine in their original packaging and slipped into a ziplock.
Remember, if you have a gardening question that you would like to suggest for this feature, post it here.
Our writers and admins will handpick a few of your questions and answer them in an upcoming Ask-a-Gardener, one of our Saturday morning features. Other questions may be moved to one of our other forums so your fellow members can help you.
The coneflower image and the hydrangea image are courtesy of Sierra77 and newlygardening, the rest are my own.
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