Category Archives: Perennials

Reblooming Iris Repeat Their Magic In Late Summer

Tall Bearded Irises invigorate summer gardens with their rainbow of colors. You’ll find nearly every shade or color combination in this beloved group of June-Blooming plants named for Iris, the Greek goddess of the rainbow. The sculptural qualities of their elegant blossoms and sword-like foliage are important design elements in perennial borders. Fragrance is often an overlooked quality, yet their perfumes are sweet and pervasive.

Reblooming Iris Collection.

Flowers appear sequentially on buds spaced along the stems, which should be cut down to the base after blooming is finished. Reblooming Iris will send up new fans that develop flower spikes as they mature later in the season, giving you a second display of showy flowers after many other perennials have passed their prime. Give them a light dose of fertilizer after the first bloom and regular watering when the things get hot.

Tall Bearded Iris Captain’s Choice boasts seaworthy shades of deep nautical blue and crisp white that combine in a commanding salute to spring.

Bearded Irises are generally easy to grow. Provide full sun to very light shade and well-drained soil. Add sand if your soil is heavy and plant so that the top of the rhizome is above the soil line. Few pests bother them, except for the Iris borer. Ward off that problem by keeping the soil around plants free of weeds and, in fall, do a thorough cleanup around plants because the borer eggs overwinter in plant debris.

Allium Globemaster

Allium – Show-Stopping Globes, Spheres, & Domes for Your Garden

As visitors stroll the display gardens at the farm, they often ask us about the plants they see in the borders and beds. No plants generate more questions than Alliums. Members of this genus are available in a broad range of colors – from various shades of purple to pink, true blue, yellow, and white, but the hallmark of this family of plants is a form that is both playful and utterly distinctive. Larger cultivars such as Alliums ‘Globemaster,’ form sizeable spheres (in this case 8-10” flower heads) that appear to float like balloons above other plants in the border. Smaller varieties including the delightful Drumstick Allium (Allium sphaerocephalon), produce lollipop-sized orbs on slender stems at a lower height.

The globe-shaped purple flower heads of Allium shown blossoming amid Salvia, Iris and Poppies in the June border.

Alliums are more commonly known as Flowering Onions, a pedestrian name unworthy of these remarkable plants.

Allium caeruleum is a standout for both its color and its form.

It’s worth mentioning that Alliums, like Daffodils, are deer and rodent resistant, thanks to their faint oniony scent. The odor is not noticeable above the ground unless the leaves are cut or bruised, and many of the flowers have an enchanting, sweet scent. There are hundreds of species within this under-appreciated genus, and we annually struggle to restrain ourselves to a reasonable selection. They are reliable perennials when they get good drainage and plenty of sun.

The flower clusters of Allium roseum bulbiferum are less dense than some other cultivars, the pink florets and airy habit adding a graceful presence to the sunny border.

Using Alliums in the Garden

Alliums offer colorful, distinctive, and long-lasting flower forms that are standouts in the early summer garden (there are some fall bloomers as well). They love sun and prefer a well-drained, even sandy, soil as long as it has sufficient nutrients. Tuck the bulbs around clumps of summer-flowering perennials where the Alliums’ withering foliage will be hidden by the expanding perennials. Some combinations we use at the nursery include Allium ‘Globemaster’ among Echinacea (Purple Coneflower); Allium sphaerocephalon (the Drumstick Allium) with Yarrow, Asiatic Lilies, or Phlox; and Allium cristophii (Star of Persia) with Salvia ‘May Night,’ Alchemilla mollis (Lady’s Mantle), or Roses. We offer 5 varieties of the shorter Alliums (10–30″ tall) as A Big Mix of Little Alliums. They look best along the edge of a shrub border or planted in front of late-blooming perennials.

Our popular Red Highlights Collection pairs Drumstick Allium with the reddish-yellow flower clusters of Achillea (Yarrow) ‘Paprika.’

How to Care for Your Allium Bulbs

Light/Watering: Most Alliums grow best in full sun, with at least 6-8 hours of direct sunlight a day. Those we offer require well-drained soil and are longest lived in locations where the soil is on the dry side during summer dormancy.

The large white globes of Allium ‘Mount Everest” are a super choice for a white garden.

Planting: Plant Alliums more shallowly than comparably sized bulbs, just one to two times the diameter of the bulb deep.

Fertilizer/Soil and pH: Alliums prefer well-drained, fertile soil. Fertilize in fall and spring with any bulb fertilizer.

Continuing Care: The leaf tips of many varieties, especially the tall ones, begin to brown before bloom time. Remove the spent flowers (except from varieties that are sterile, such as ‘Globemaster’) if you wish to prevent them from self-sowing.

Pests/Diseases: Alliums have few problems except when planted too shallowly or in wet soil.

Companions: Place Alliums behind heavy-foliage plants such as Peonies and Iris. Good for bedding, and in mixed borders. Flower heads are good for drying.

Alliums pair beautifully with a wide variety of perennials including Echinacea (Coneflower), Phlox, Alchemilla mollis (Lady’s Mantle), Achillea (Yarrow), and Iris. Peonies are another excellent choice. Here a purple-flowering Allium pairs with a white-flowering Peony.

Dividing/Transplanting: Alliums rarely need transplanting or dividing, but this can be done when the bulbs are dormant.

Asclepias tuberosa: Essential Monarch Food & a Whole Lot More

Asclepias tuberosa, our native Butterfly Weed, has long been a favorite in the borders, beds and meadows here at the farm. In recent years, it’s attracted significant attention as an essential source of food for Monarch butterflies who feed on it during their larval stage. (For more information about its role in sustaining Monarchs, visit the website for the Xerces Society for Invertebrate Conservation.)

This year, it was named the 2017 Perennial of the Year by the Perennial Plant Association.

Asclepias tuberosa
The nectar-rich blossoms of Asclepias tuberosa provide food for a wide variety of pollinators.

We have long encouraged plantings of Asclepias tuberosa (pronounced uh-sklee’pee-us) because, in addition to providing food for Monarchs and nectar for a wide variety of pollinators, it’s a boldly colorful bloomer that provides four seasons of interest in the garden. Hardy in zones 4 through 9S and 10W, it grows a modest 1- to 2-feet tall, making it ideal for the edge of the border. The plants produce clusters of brilliantly colored, nectar-rich orange blooms from July through September. (Asclepias tuberosa ‘Hello Yellow,’ an enhanced native variety, grows 2–to 3-feet tall and produces yellow flowers.) These plants shrug off drought, do well even in poor soil, and are deer resistant.

ASCLEPIAS TUBEROSA (YELLOW FORM)
Asclepias tuberosa ‘Hello Yellow’

As autumn arrives, Asclepias tuberosa’s seedpods add interest to borders and beds. The slim, decorative pods are filled with papery seeds. As the season progresses, the pods split open, and the seeds, which are attached to silky white parachutes, scatter in the wind. The plant’s pale, empty husks remain, and as winter settles in, the pods look magnificent coated in frost and then in swirling snow. The winter beauty of this plant is not lost on Dutch designer Piet Oudolf who included Asclepias tuberosa in his design for New York City’s High Line.

milkweeds-022-620x416_deborah-silver
Milkweed pods. Photo courtesy of Deborah Silver of Deborah Silver and Co.

A 2014 post on the Friends of the High Line blog notes: “The intricate flowers [of Asclepias tuberosa] are stars of the garden in the summer, but the empty husks of the seed pods remain an integral part of the winter garden as well. These oblong golden-gray husks are dry and slightly twisted, warped from the process of drying out. The outsides are rough and gray, with a hint of gold when the light is right. The insides are soft white, reminiscent of the silky hairs that caught the wind and carried the seeds away. These pods crown the remnant skeleton of the stem, providing a subtle, textural beauty during the deep cold of winter. These structures remind us that to High Line planting designer Piet Oudolf, ‘the skeletons of the plants . . . are just as important as the flowers.’ ”

When planting Asclepias tuberosa, be mindful of a few things. It grows best in full sun and well-drained soil (sandy soil is ideal; clay and heavily enriched soils are not). After planting, water the plant deeply then hold off until you see it begin to wilt a bit. If your Asclepias tuberosa develops yellow, chlorotic-looking leaves, it’s an indication that you’re over-watering.

Since some perennial Milkweed varieties are among the last to emerge from dormancy in spring, you might want to mark their location so you don’t plant something on top of them.

Asclepias tuberosa, zinnia zowie
Create a tone-on-tone palette by planting Asclepias tuberosa with other orange-flowering plants including Zinnia ‘Zowie! Yellow Flame.’

Design-wise, as with many additions to the garden, Asclepias tuberosa is most effective planted in clusters of three or more. To create an eye-popping contrast of colors and flower forms, showcase the bold bright orange blossoms alongside the deep purple flower spikes of Salvia ‘May Night’ and Liatris ‘Kobold.’ For a tone-on-tone effect, our head gardener has planted orange-flowering Asclepias tuberosa amid a sea of other orange bloomers such as Zinnia ‘Profusion Orange,’ Echinacea Butterfly™ ‘Julia,’ Butterfly™ ‘Postman,’ or Prairie Pillars™ ‘Flame Thrower,’ and Helenium ‘Short ‘n’ Sassy.’ In meadow gardens, the orange flowers pair beautifully with ornamental grasses including the 18”–30” Pennisetum ‘Hameln’ and the blue spiky foliage of Festuca glauca Beyond Blue™. They’re also a terrific companion for Amsonia hubrechtii, which has green needle-like foliage that turns into a cloud of yellow in fall.

Liatris spicata Kobold, Stokesia, Asclepias tuberosa
Asclepias tuberosa with the purple flower spikes of Liatris spicata ‘Kobold,’ and the deep lavender blossoms of Stokesia (more commonly called Stokes’ Aster).

Be aware that Asclepias tuberosa does not appreciate being moved once it’s settled in. The plants produce deep taproots that are better left alone once planted, so site it with care, let it be, and enjoy all of the benefits of this tremendously valuable plant.

 

 

The Wide World of Peonies

Peonies are one of the great glories of the late spring garden. The silky soft, colorful, often fragrant blooms have a natural opulence that make them as treasured in the garden as they are in vases in the house. The gorgeous blossoms are produced by remarkably carefree and robust plants that require almost no maintenance and take twitchy spring weather in stride. In addition to producing lovely flowers that are superb for cutting, the value of their foliage should not be overlooked. In the early spring garden, the reddish-green stems of emerging herbaceous peonies make a fine companion or backdrop for daffodils, tulips and other early spring arrivals.

Planting and transplanting peonies of all types should be undertaken with a bit of care. Click theses links to find all the advice you need along with helpful tips for planting and growing  herbaceous and tree peonies.

To help choose the right peony for your garden, start by familiarizing yourself with the different types. Here are three of the most common:

Herbaceous Peonies

oldtime
White Flower Farm’s Old Time Peony Collection

These long-lived perennials range from exquisitely delicate singles to large and lush doubles, with shades from pure white to the deepest red. Here in Connecticut, they usually produce their display in June, and their glossy, deep green leaves look good all season. Peonies make superior cut flowers, lasting more than a week if cut in full bud.

An important thing to understand about Herbaceous Peonies is that they die back to the ground in winter and send up new growth in spring. For this reason, they’re generally classified as perennials. (Tree Peonies, see below, have woody stems that retain their structure year-round, so they’re classified as shrubs.)

Intersectional Peonies

bartzella
Intersectional Paeonia ‘Bartzella’

A cross between Herbaceous and Tree Peonies, these plants generally blossom between Tree Peonies, which are first to blossom, and Herbaceous Peonies. By planting Intersectional varieties, you extend the Peony blossom season in your garden, creating a continuous flow.

Tree Peonies

Tree
White Flower Farm’s Tree Peony Grove

In its native China, the Tree Peony (Paeonia suffruticosa) ranks as a national favorite, and it’s easy to see why. These hardy shrubs produce exquisite floral displays, with silky blooms measuring up to 10” across in May and June.

Tree Peonies are woody plants that retain their structure year-round. Slow to mature, don’t be surprised if there are few or no flowers the first spring after planting; plants generally take a few years to settle in and bloom heavily, but mature plants reach 4–5’ and bear up to 50 showstopping blooms. Deer and disease resistance add to their appeal.