Have you noticed some leaves taking on fall colors early? At first, I thought a few trees had been pushed past their stress limits and weren't going to survive. But then I saw it: Starting at the tips of the leaves, the green melts into purple, maroon, auburn, and gold.
Last year, leaves didn't start to turn colors until the second full week of September. This year, the process is starting two or three weeks earlier.
Chris Bloomfield, a certified arborist and master gardener, sees a few trees changing color at the Stranahan Arboretum.
"There are a few maples and serviceberry trees that have started to turn," he says. But not all trees are turning because of fall-like weather. "For some trees, it could be from stress, insect damage, or even disease. We have had a couple of hornbeam trees die this year. But we have linked it to second year drought stress."
Mr. Bloomfield also says a cool summer can trick trees into changing colors early.
When nights get cooler and days get shorter, plants start preparing for winter.
With lower temperatures and less light, chlorophyll production slows and eventually stops. Warm days and crisp nights bring out the most brilliant colors in the leaves. Inside the tree, lots of sugar is being produced, but the veins going to the leaves are closing and the food isn't able to reach the foliage.
The daytime sun triggers production of colorful pigments. Carotenoid is one of them. It turns plants yellow, orange, and brown. You find it in corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas. Another pigment, anthocyanin, produces red and purple colors in fruits such as cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums.
The green color goes away, leaving the other chemicals to show off their colors on the surface of the leaves.
Once the tree cuts off food to the leaves and they have shown their colors, there is nothing left to do but dry up and drop.
Trees aren't the only plants changing colors. If you have ornamental grasses in your landscape, maybe you have noticed their beautiful seed heads dancing gracefully in the breeze. Sedum is just starting to turn pink and will show up the rest of the perennials in a few weeks with its maroon tufts of blossoms. Asters, heather, plumbago, salvia, dahlia, lavender, and late flowering clematis are a few plants in the border that are coming on strong. Chrysanthemums aren't the only fall bloomers out there. Anemone, black-eyed Susans, shasta daisies, blanket flower, butterfly weed, hollyhock, hosta, obedient plant, penstemon, Russian sage, and yarrow will keep your perennial bed blooming well into frost.
Take advantage of the warm weather and get those fall bulbs in the ground. It is also great weather to seed a lawn. There's always something fun to do when you are a gardener!