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"The Best Autumn-Blooming Perennials" Think of fall, and autumn leaves come to mind. The arrival of autumn brings with it cooler temperatures and shorter days. The arrival of autumn does not mean the end of bloom in the garden, however. Autumn is a time when many perennial flowers come into their own. Fall-flowering perennials keep the garden in colorful bloom through frosty weather when all other flowers have gone by. These late-summer and fall-blooming perennials are otherwise inconspicuous in the garden in spring and summer, but when the end of the season nears, they come forth in a flurry of bloom that starts in September, continues through the killing frosts of October, and many persist into winter and beyond to provide winter interest. Click on a plant name below to order it from Pernell Gerver's Online Store. Beginning to bloom in late summer and continuing right to frost, white hardy begonia is a lesser-known perennial that should be grown more. It's a rare perennial that has light-green, angel-wing-shaped foliage with maroon undersides and deep-red veins. Its flowers are pure white and begin blooming in midsummer and continue to frost. It self sows, increasing the original planting. It grows 12 to 18 inches tall and wide and thrives in shade to part sun. Sedum 'Brilliant' begins blooming in late summer and continues into fall. It bears large, flat-topped clusters of brilliant-pink flowers atop attractive, chartreuse, fleshy foliage. Instead of deadheading the flowers once they go by, I leave the flowers on the plant through winter because they catch and hold snow, providing winter interest. Sedum 'Brilliant' forms a handsome clump a foot and a half tall and wide. New England aster 'Purple Dome' is one of the more desirable asters because of its compact plant habit, eliminating any need for pinching to keep the plants short and bushy. 'Purple Dome' is aptly named because it forms a perfect dome of purple flowers 18 inches high and wide. It doesn't begin blooming until late in the season and is a good substitute for mums. Japanese anemone 'Pamina' is one of the best varieties of Japanese anemone. It forms a handsome mound of foliage not quite two feet tall - no staking required! Flower stems rise through the foliage and stand three feet high. Dozens and dozens of rosy-lavender flowers bloom over a long period from early September right through frost. The double flowers have many petals surrounding a central cluster of orange stamens. It grows to 30 inches tall with the flowers. Dendranthema 'Sheffield' is truly a "hardy" mum. It comes back reliably year after year. It's also one of the last plants to bloom in my garden. It bears single, salmon-pink, daisy-like flowers on stems that can grow to three feet tall. The flowers begin blooming in late October and have been in bloom in my garden as late as Thanksgiving. It will be in bloom long after frost has claimed the annuals and most of the other perennials. It combines nicely with the other autumn-blooming perennials and extends the bloom season well into fall. Two fall-blooming bulbs called colchicum provide colorful flowers late in the season. They're rather rare and lesser known, but they definitely deserve a spot in any garden. The variety 'Lilac Wonder' bears huge lilac-pink, crocus-shaped flowers that burst out of the ground with no warning in autumn. Foliage appears in spring, then dies back. A mature bulb can produce 20 or more flowers. 'Waterlily' bears striking, bright lilac-pink double flowers that look just like a waterlily bloom. They also appear in autumn without foliage. The leaves grow in spring, then die back. A very choice and hard to find cultivar.

by Pernell Gerver

"Mulches Serve Different Purposes" Q. What's the deal with mulch? Do I remove summer mulch before winter so that the ground can freeze (this is in a perennial garden) or can I just leave it on and let it double as a winter mulch? If it's better to remove it, can it be used the following year? Thanks. A. Summer mulch and winter mulch serve two different purposes. A summer mulch stays on the ground all year long and is used to reduce weeds, conserve soil moisture, and moderate soil temperature by shading the ground from the hot summer sun. A winter mulch is used to keep the soil frozen and prevent the alternate freezing and thawing cycle that occurs usually in January - known as the "January thaw." Summer mulches are applied to the ground around plants, but never over the crown, or center, of the plant. When applying a mulch, stay away from the plant a couple of inches. Put on a good thick layer about three to four inches deep. Mulches I like to use in flower beds and landscape plantings include shredded bark mulch or leaf mold. Summer mulches do not have to be removed from the ground to allow the soil to freeze. The ground will freeze beneath the mulch and the mulch will also freeze. Ground that is mulched will freeze later than bare ground. Winter mulches are applied to perennial beds after the ground has frozen. A winter mulch helps keep the soil frozen by shading the ground from sunlight. A winter mulch should be applied in a thick layer and should cover the entire bed, including over the tops of plants. Choose a material that is non-matting to allow for good drainage. There are many different types of winter mulches, but one of the most common ones to use is pine boughs. Lay the pine boughs in a crisscross pattern on top of one another so they are two layers deep. Salt marsh hay is also a good non-matting mulch to use as a winter mulch. A winter mulch should be gradually removed in spring, as new growth begins to appear. If you use salt marsh hay as a winter mulch, when you remove it from the flower beds you can reuse it in the vegetable garden as a summer mulch in beds and walkways. Click here to read more about winter mulch and order it from Pernell Gerver's Online Store. Click here to submit gardening questions for Pernell Gerver's online Q & A column. Click here to read previous online columns in the archives.

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