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Ohio Prairies Each Season
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Ohio Prairies Each Season
Late Summer – August and September
Late Summer. In August and September, the prairie is in full maturity, with the tallgrasses and forbs (“wildflowers”) at full height. Tallgrasses reach six to eight feet high, with seedheads forming. The late season flowers, such as prairie dock, tall coreopsis, and many others bloom in profusion on their tall stems that match the height of the grasses.
The common flower color centers on the bold yellows of the sunflowers and other composites. A few species are white or blue, but yellows predominate.
Prairie flowers in late summer attract butterflies and other feeding insects.
In September, prairie grasses and forbs (the “wildflowers”) begin to fade. The chemicals that made to plants green or the flowers colorful in August are being re-absorbed by the plants and sent in converted forms down to the roots where they will be stored to be used for new growth next spring. The spring fires will burn off the dead stems and leaves, but the rootstocks will be safe beneath the soil, filled with stored chemicals that will fuel quick new growth. Those chemicals, mostly sugars and other carbohydrates, are being profusely formed and stored in late summer. Next year’s first growth will be powered by chemicals formed now.
Flowers are being pollinated by insects and wind, prompting the growth of fertile seed within the flowers or seedheads. But be aware that in mature prairies, very few seeds ever germinate and grow into new plants. Almost all the plants on a mature prairie are long-lived perennials, perhaps hundreds of years old. Seeds can grow into new plants only where and animal, erosion, or human activity has destroyed a patch of prairie. Unlike garden plants, almost all prairie plants can grow to great age. Most plant reproduction on prairies is “vegetative,” with the growing of new stems or rhizomes (underground stems) growing out each year. The oldest living plant in Ohio is probably a prairie grass plant, not an ancient oak tree.
Autumn – October and November
Autumn. By October, most prairie flowers have matured and dried and have "gone to seed." In October, the seeds of the tallgrasses will mature and begin to drop away from the seed heads. Forb (prairie "wildflower") seeds often remain in the dried flowers for some time. Goldfinches and other seed-eating birds commonly drop onto autumnal prairie plants and consume the seeds.
Flowers and leaves have faded. The robust summer greens and flower colors have disappeared as the plants have chemically digested cellular components and returned them to roots and rhizomes beneath the soil surface. These re-absorbed plant pigments and other chemicals will provide energy and chemicals for the plants' re-growth next spring. During the winter, the old stems and leaves will stand dead in the prairie. They are composed mostly of cellulose and in the spring will provide fuel for rejuvenating prairie fires, or they will create a dense, cool mulch that unless burned off will retard the start of next year's growth.
Prairie invertebrates, including moths, spiders, and other "bugs" have for the most part also retreated to the safety of the prairie soil to pass the cold, dry winter. Some moth and other insect larvae spend the year dormantly in above-ground stems. Prairie fires destroy these larvae. Consequently, it may be wise to leave portions of prairies unburned during prescribed fires.
Winter – December, January, and February
It's Winter! Ohio prairies are senescent, “sleeping,” as it were. No plants are growing, Chemical energy reserves (carbohydrates and lipids) have been sequestered below ground in roots, rhizomes, and tubers, awaiting the warm up in April. These chemicals will be used by prairie perennials to initiate the first growth, to push up new stems and leaves. Last year's stems and leaves above ground are slowly decaying.
No cells are dividing or elongating. Physiologically very little is happening. Not much above ground is alive. Voles and mice are eating seeds and chewing on bits of living plant material at the ground surface. Insects and other arthropods are either passing the winter as eggs deposited in the ground or in plant tissues, or as senescent winter-adapted adults. Snakes and amphibians have retreated to underground or sheltered places. Most birds have left the winter prairie, as there is little food during this season. Large mammals will travel through a winter prairie, but there is little there for them to eat.
Seeds are vernalizing, which means they are "counting" the number of cold, damp, and dark days or hours. Until enough time has been spent at reduced temperatures, most prairie seeds won't germinate. So, if a week-long warm spell hits in February or March, native prairie seeds won't make the fatal mistake of starting to grow too early. A seed that germinates in mid-March will die as a frost-bitten seedling in late March.
The prairie in winter is not very biologically active. But aesthetically, the lay of frost, snow, and rain on the winter grasses can be particularly beautiful.
Early Spring – March and April
Early Spring! Ohio prairies have passed another winter. The live growing parts of prairie plants are safely below ground, awaiting warm soil to begin new growth. Above ground, there is a covering mass of the now-dead stems and leaves of last year's vegetation. Snow and ice have pushed this low to the ground in most cases. While present, this "duff" – dead vegetation – will act as an insulator and retard the prairie’s new growth in two ways.
First, the dead stems and leaves will insulate the soil from the warm air and sunshine of spring. Prairie plants grow only when soils are warm, so the duff layers retard new prairie growth by keep soils cool.
Secondly, newly emerging stems and leaves are shaded by the duff, which can be several inches thick. Consequently, photosynthesis can’t begin until the new shoots push up through the duff. The duff is a prairie-negative, slowing new growth, effectively shortening the prairie’s growing season by as much as three weeks or more, reducing the size and vigor of the new season’s growth. Prairies grow best without the retarding effects of last-year’s duff.
Ideally, the duff should be removed before new growth begins in April. If you have a backyard prairie, now is the time to rake off last year’s dead stems and leaves. This duff makes good compost or garden mulch. Rake off your prairie plot and watch the fine results.
But on large prairies, the only effective duff removal technique, one that has been used by humans for thousands of years, is fire. March and April are the prairie fire months. Park districts, wildlife areas, and other large prairies are being burned – but only under certain conditions.
Don’t entertain any ideas of setting a prairie fire on your own. Without knowledge and experience, prairie fires can be very dangerous. With knowledge and experience, prairie fires are virtually without hazard. Leave fires to the experts.
In order to safely and legally burn a prairie in Ohio, specific written permission must be obtained from the Ohio Environmental Protection Agency. Prairie fires come under Ohio open burning regulations, and contrary to what any local township, county, fire, or law enforcement official might say, an OEPA open burning permit is always required.
Secondly, any prairie fire set between 6 a.m. and 6 p.m. in the months of October, November, March, April, and May (outside city limits) requires written authorization from the Chief of the Ohio Division of Forestry. Authorizations are given only to Ohio Certified Prescribed Fire Mangers registered by the Ohio Division of Forestry.
Consequently, prairie fires can’t be set by merely tossing a match. State Forestry and EPA laws and regulations must be strictly followed.
Ohio prairie managers prefer to burn their prairies in March and early April. After a day or two of warm (approx. 50deg F or more) winds, prairie duff dries and becomes flammable. Prairies should be burned only under ideal prairie fire weather conditions, taking into account wind direction and speed, vertical atmospheric conditions (mixing height, transport speed, others), fuel loads, fuel moisture content, fuel breaks, and several other parameters. Again, prairie fires are only for the knowledgeable, experienced, and authorized.
With everything in place – proper permits, trained crews, proper prescribed fire equipment, a detailed burn plan, and much more – prairie managers are setting Ohio prairies on fire in March and April. If you see a prairie being burned, don’t think of this as anything destructive. A prescribed prairie fire is rejuvenating and enhancing. It removes the growth-retarding duff, begins the warming of the soil, and allows newly-emerging sprouts to grow strongly without any shading.
There are few natural events as powerfully awesome as a restoring landscape prairie fire. Prairie fires begin the new prairie year. After a fire, the blackened prairie landscape looks completely destroyed and void of any life. But prairie plants will then joyously explode out of the cleared ground in April and May.
Fires give new life to a prairie. With the cleansing fires, a new prairie season starts.
The Ohio Prairie Association strongly advises against anyone attempting to conduct a prairie fire who does not a) have experience with prescribed prairie fires, b) who does not have required legal authorizations from the Ohio EPA and Ohio Division of Forestry, and c) who does not have essential fire-conducting resources (such as proper attire, ignition equipment, and fire suppression sprayers, etc.).
If improperly conducted, human-set prairie fires can be dangerous. Prescribed prairie fires should be planned for and conducted only by those knowledgeable and experienced in such fires.
Late Spring – May and June
Late Spring. After spring fires, Ohio prairies are now beginning to grow rapidly. Especially when last year's dead, insulating vegetation has been burned off, soils warm quickly, prompting strong growth from roots and rhizomes that have stored carbohydrates from last season’s growth. These carbohydrates power the early growth of most prairie plants, getting the tender shoots high enough to be begin strong photosynthesis.
Remember, the early growth of all prairie perennials is powered by stored reserves from the previous season.
Not many forbs (“wildflowers”) are yet in bloom, but many early-season forbs are shooting up quickly above the grasses. They will bloom in June and July, and then will fade away as the tall grasses overtake them. Later, other forbs that will stand above the taller grasses.
The few small spring prairie forbs, such as blue-eyed grass (Sisyrinchium albidum), are beginning to mature or fade. Their few weeks in the sun is passing as other forbs and grasses continue to grow above. At the beginning of June, Ohio prairies are typically about 12 - 16 inches tall.
Early Summer – Late June and July
Early Summer. By now, soil temperatures have finally warmed, prompting full prairie growth. The major prairie grasses grow in warm conditions, particularly when soils have warmed. The tallgrasses are growing vigorously now, with lots of leaf area. Toward the end of July and into August, stems will form.
In late June and July, not many prairie wildflowers are yet in bloom. Prairie growth now is primarily vegetative, not reproductive. Plants are growing new photosynthetic leaf areas and beginning to accumulate carbohydrates that will support flowering later in the summer.