Large-flowered perennials – season extensions

Large-flowered perennials – season extensions

Andrew Bunting

Some gardeners may think that cooler fall weather means that the ornamental value provided by flowering perennials should also leave the season.

A wide variety of flowering perennials bloom in the fall, providing beauty and scenery. Many of these varieties are also native, so gardeners can help support local ecosystems while maintaining a stunning fall garden.

Asters, the best of the best

Doellengeria umbellata is a large, strong, flat aster with an abundance of white flower clusters. This aster can grow up to five feet tall and can spread across the garden to form bold clumps. It is an ideal plant for its abundance of flowers in the fall.

Eurybia Macrophylla, the large-leaved aster, also makes a bold impact in the garden with a slightly smaller stature and soft white or purple petals. Both Doellengeria and Eurybia are effective in large, sweeping clumps.

The flower power of Symphyotrichum oblongifolium, the fragrant star, is unparalleled.

Popular varieties, ‘October Skies’ and ‘Rydon’s Favorite’ become spiraling clumps up to 2 to 2 1/2 feet tall.

In early October it becomes covered in lilac to blue, quarter-sized flowers with a yellow center. It is also one of the best asters for attracting pollinators to the garden. Fragrant aster, like all of the above, thrives in full sun.

At the Subaru of America campus in Camden, New Jersey, the Pennsylvania Horticultural Society uses the soft aster, Symphyotrichum laeve ‘Bluebird’, for a late-season pop of color.

The flowers are a stunning powder blue and are set on erect stems that range from two to four feet high.

In the wild, it has a wide native range in almost every state east of the Mississippi River. At Subaru, they are a favored perennial for their tough urban durability.

Symphyotrichum ericoides, the white star with small, narrow foliage. It’s like some earth covering the juniper.

‘Snow Flurry’ is a gorgeous selection that has an abundance of small white flowers. This is a great plant to use in a rock garden, draped over a wall, or as a ground cover in a sunny location. It can also be used in large quantities as a ground cover plant.

For shade, Eurybia divaricatus, white wood star is a great choice.

It is a wonderful compliment when used in large quantities under river birch trees, Betula nigra.

The beautiful, creamy, exfoliating bark is a lovely combination with small, frothy white flowers in late summer through early fall. This is one of the few asters that will bloom in partial to full shade. It combines well with many sedges (Carex), as well as foam flower (Tiarella) and the Christmas fern, Polystichum acrostrichoides.

Native ironweed

In the past 10 to 15 years, native ironweed—once considered a roadside weed—has become an important part of the fall garden.

This aster features bright purple flowers. Depending on the species, they can be compact plants, only 2 feet tall, or towering perennials over 12 feet tall.

Vernonia lettermannii ‘Iron Butterflies’ features narrow foliage that turns golden yellow in fall. Above this soft-textured plant is an abundance of small purple flowers that are great for attracting pollinators late in the season.

Vernonia noveboracensis, New York ironweed, grows five to seven feet tall and is a wonderful addition to the back of a flower border. Vernonias are also urban hardy and can tolerate long periods of drought.

Big gold bars

For decades, goldenrod was falsely accused of being the source of hay fever, which, as we now know, was most likely caused by ragweed plants, which flowered at the same time.

There are dozens of native species of Goldenrods and many cultivar choices as well. They light up the fall garden with bright, cheerful golden blooms perched atop stiff stems.

The showy goldenrod Solidago speciosa grows up to three feet tall with thick, very showy bright yellow flowers.

Solidago sempervirens, coastal goldenrod, is native to eastern coastal areas.

Because of its salt tolerance and ability to grow in sandy soil, it also does well in urban gardens.

One of the first goldenrods to be popularized was the “firework” Solidago rugosa, the raw goldenrod.

Reaching only two to three feet tall with an even spread, it is an excellent choice for a smaller garden. In early fall, it has open clusters of golden flowers that look like explosions of “fireworks.” This resembles the floral display of ‘Solar Cascade’. These plants can reach four feet tall.

Shadow lovers

The hardy begonia, Begonia grandis, has an abundance of pink flowers suspended in loose panicles around the foliage.

Reaching 18 to 24 inches tall, it becomes a relatively fast-growing ground cover in shady parts of the garden. The abundance of pink flowers brightens up the forest garden, and the leaves are very decorative. Once the blocks are established, they will be seeded across the garden.

“Alba” is a white host selection. While most hostas are grown for their gorgeous foliage in the shade garden, Hosta Taridflora has attractive spear-like leaves and in early fall has abundant spikes of lavender-purple tubular flowers. The flowers are a source of late nectar for local hummingbirds.

Almost all toad lilies, Tryicyrtis, bloom in late summer or early fall. Ricyrtis macrantha Susp. Macranthopsis is ideal for planting in a container or at the top of a wall where the drooping foliage can cascade down.

The stems are covered with tubular, teardrop-shaped yellow flowers. Tricyrtis hirta, the Japanese toad lily, has white, orchid-like flowers facing upwards on stiff stems with purple-black spots.

As the home garden transitions from an abundance of summer flowers to fall, there are many great choices for flowering perennials, such as asters, goldenrods, ironweed, begonias, hostas and toad lilies. Can be used to extend the ornamental period of the garden. Many of them not only have a long flowering period, but are also native and serve a variety of ecological functions such as being hosts for late bloomers in the garden.

Used with permission of the Pennsylvania Horticultural Society of Philadelphia.

Andrew Bunting is vice president of horticulture for the Pennsylvania Horticultural Society and vice president of the Swarthmore Horticultural Society.

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