Top Ten Perennial Picks for Jazzing Up Your Garden

While attending New England Grows earlier this month, a trade show that highlights new trends in landscaping and horticulture, I heard that Tony Avent was scheduled to speak. His topic was “100 Perennials I Wouldn’t Garden Without”, and I knew I couldn’t miss it. Tony Avent is a plant explorer, hybridizer, all-around plant guru, and owner of the famous Plant Delights Nursery, a mail-order and retail nursery in North Carolina. This exciting nursery is dedicated to offering the best, the newest, and the strangest garden-worthy perennials to gardeners around the world

Tony’s enthusiasm about plants is contagious. I walked away wanting to try every plant he mentioned, but was able to create a short-list of ten fabulous, unusual perennials.

Japanese Peony (Paeonia japonica). A peony that prefers shade! Most peonies are sun-lovers, but not this charming woodland peony. It makes an 18" x 18" clump of grey-green foliage that is topped in early spring with lovely 3" wide white cups with yellow stamens. After flowering, pods form that split open to reveal incredible, gorgeous metallic-blue seeds on red stalks. The Japanese peony is recommended as a deer-resistant specimen in the woodland garden and in the shady perennial border.

Bush Clematis (Clematis integrifolia ‘Rose Colored Glasses’). Clematis integrifolia, also known as solitary clematis, is a non-climbing herbaceous perennial that forms a dense, sprawling mound 12-24” tall. The cultivar ‘Rose Colored Glasses’ produces two-inch long flowers that are rose-pink, nodding, and urn-shaped, with twisted sepals. Each flower appears singly atop its own slender stem and is followed by ornamental silver-green seed heads. It has an incredibly long bloom time, from May to July, with continued lesser bloom into September. It flowers best in full sun with adequate moisture and makes a beautiful addition to cottage gardens, meadow gardens, and perennial borders.

Heucherella ‘Solar Eclipse’.  This amazing little plant forms 16" wide clumps composed of dark purple leaves, each edged in a ring of chartreuse. It strongly resembles a zonal geranium. It retains its intense color throughout the growing season. It is topped in late spring with bottle-brush spikes of white flowers. I have grown other Heucherella cultivars, and they are easy, relatively pest-free and offer dramatic foliage. I can’t wait to try this one! Heucherellas require part sun to light shade. It should be planted in regular garden loam and looks lovely in shady gardens accompanied by hosta, epimediums and other shade-loving perennials.

‘Millenium’ Allium. This allium forms a 1’x1’ clump of narrow, glossy green leaves that is topped by 2” rose-purple flowers in late summer. Very floriferous, it will bloom for over a month. I was especially interested in it when I heard that it is the product of a hybridizing program of a well-known allium breeder from Massachusetts, Mark McDonough. Plant Allium ‘Millenium’ in full sun and this deer-resistant little plant will reward you with a full season of shiny, strappy foliage and a stunning floral display.

‘Tomato Soup’ Coneflower (Echinacea ‘Tomato Soup’). Plant hybridizers have been expanding the color-range, size and form of our native perennial coneflower. This new introduction, ‘Tomato Soup’, forms a 32” tall clump that is topped in summer with flowers that are indeed the color of tomato soup. The 5” wide blossoms are attractive to hummingbirds and bees, and its seeds are favored by birds. Echinacea are sun-loving, drought-tolerant perennials that require excellent drainage, particularly in winter.

‘Low Down’ Swamp Sunflower (Helianthus angustifoius ‘Low Down’). Finally, a swamp sunflower for the small garden! Our native Helianthus normally reach heights of 8 feet, suitable for the back of the perennial border. But this new cultivar produces 18”x18”clumps for the mid-border, that are covered in September with large, yellow sunflower blossoms. Native to the US, swamp sunflower is a sun-lover that performs well in both wet and dry soils.

Hosta ‘Dixie Cups’. This hosta is a Plant Delights Nursery introduction, and was hybridized by Tony Avent himself. I love the name. It is a medium-sized blue hosta with leaves that are cupped and corrugated. It requires part sun to light shade with adequate moisture and would look lovely planted with purple-leaved heucheras, ferns and golden Hanoke grass.

Bristle-leaf Sedge (Carex eburnean). This little grass is native from the east coast to the west coast and is hardy in Zones 2-8, yet it is an uncommon sight in the home garden. It produces 8” wide clumps of soft green, narrow foliage. Amazingly, it is one of the few grasses that will grow well in the shade. It is drought-tolerant and deer-resistant, and looks great in the woodland garden as well as the rock garden.

Sedum ‘Frosted Fire’. Sedum ‘Frosted Fire’ is a gorgeous variegated hybrid of the popular Sedum ’Autumn Joy’. It produces 15”x15” clumps of fleshy green foliage edged in cream. It is topped in late summer by red flower heads that age to bronze. Sedum ‘Frosted Fire’ is drought-resistant and easy to grow in full sun, but dislikes wet soils.

‘Lightning Strike’ Toad Lily (Tricyrtis hirta ‘Lightning Strike).  This variegated Tricyrtis makes an outstanding addition to the shade garden. Its 2’ tall arching stems are clothed with golden leaves streaked with green. In early fall, light lavender spotted flowers, appear along the stems at the leaf axils. This unusual plant is very easy to grow in conditions similar to those preferred by hostas. In fact, it makes a perfect companion plant with hostas , ferns and heucheras in the shady border.

I am already looking forward to a new growing season and am eager to give my new Top Ten Picks a try!

Hellebore 'Snow Bunting' is Sure to Please

Hellebore 'Snow Bunting' is one of my favorites - an early bloomer in my Zone 5 garden. Its buds begin poking out of the ground in early December, and depending on the severity of the winter, will open in February or March.

This hellebore is an unusual plant from the esteemed Yokoyama Nursery in Japan, a difficult to produce hybrid between H. niger and H. x hybridus.

Each plant produces a beautiful bouquet of pure white, outward-facing flowers that last for months, turning a soft light green as they age. A lovely sight!

Geraniums: Delicate Beauty for the Perennial Garden

During a recent garden tour, I pointed out a clump of beautiful hardy geraniums to my friend, and got the usual confused look. Upon hearing the term ‘hardy geraniums’, most people look for Pelargoniums, whose big, bright blooms adorn millions of flower boxes and porch planters. The term ‘hardy geranium’ however, refers to a genus of delicate mounding perennial flowers ranging in color from cornflower blues to soft pinks, mauves, purples and  deep maroons. Also called “cranesbills” for the shape of their seedpods, hardy geraniums have flowers and foliage that are smaller and finer than those of pelargoniums, and reward the gardener by returning reliably and blooming profusely year after year.

I grow only six of the 400 species of hardy geraniums that have been identified. The plants are perfectly adapted to Massachusetts gardens, thriving in zones 4-8. Most form low, dense mounds with small cup-shaped flowers that float above the foliage on thin stems, attracting bees and butterflies. The translucent flower petals look particularly beautiful when backlit. While all species exhibit five-petaled, symmetrical flowers and finely divided palmate leaves, some have contrasting splotches or veining. Even when not in bloom, hardy geraniums add beauty to the garden from spring through fall with their leaf shapes color variations.

Hardy geraniums are extremely flexible plants, and whether you are looking to fill a dry, sunny spot, an area with part shade or a groundcover for the woodland garden, you will find a geranium that will suit your situation. I love to use Geranium sanguineum, also known as Bloody Cranesbill, in place of annuals at the front of a border. The plant forms a low (8”), wide mound with a profusion of magenta flowers light up the garden all summer long. In my garden it is gorgeous combined with purple heuchera, lamb’s ears, ‘Blue Star’ juniper and bearded irises.

For those that love masses of true blue, billowy flowers, there are two wonderful geranium varieties: ‘Johnson’s Blue’ and ‘Rozanne’. ‘Johnson’s Blue’ forms 18” mounds of cornflower blue flowers that grace my perennial bed for the month of June. ‘Rozanne’, awarded the title of  “2008 Perennial Plant of the Year”, is  taller with 2.5 inch violet-blue flowers that bloom all summer, and deep green foliage lightly marbled with chartreuse. I fell in love with it when I saw the “Rozanne River” in the Bressingham Garden at Elm Bank.

I recently acquired my first Geranium phaeum, also known as Mourning Widow or Dusky Cranesbill from the Cotton Arbo-retum in Winchester, Mass. Geranium phaeum is one of the taller species, up to 32” in bloom, with purplish brown spots on its leaves and deep maroon, almost purplish black flowers. This geranium can be grown in dry shade and combines superbly with chartreuse hostas and hanoke grass.

Although it is difficult to chose a favorite geranium species, my favorite is Geranium macrorhizum (Bigroot geranium) with its bright pink flowers in early spring, scented foliage which turns a bright scarlett in autumn, and its tolerance of dry, shady areas. I am partial to any plant that survives under my massive maple trees and adds so much beauty to such an inhospitable site.

Hardy geraniums require little care once established. They prefer moderately rich soil, and have no significant pests or diseases. I shear my plants back to their basal foliage once in mid-summer to encourage new leaf growth and reblooming. (The only exception to this is Geranium macrorhizum, which can be deadheaded and needs no shearing.) Geraniums live longer if divided every 3-5 years, and your friends will be happy to receive divisions of these wonderful plants for their own gardens.

Snowdrops Carpet the Early Spring Garden

Few flowers are more appreciated than the first blossoms of spring. One of the earliest flowers is the diminutive snowdrop, usually blooming several weeks before crocuses appear. Often emerging out of a blanket of snow, the aptly named snowdrop flower resembles three drops of milk hanging from a stem. Its Latin name, Galanthus, means “milk-white flowers.” The plants grow to a height of 4-8”, and exhibit beautiful bright white blossoms punctuated with a bright green spots, and a faint honey fragrance.

Although there are more than 70 varieties of snowdrops in cultivation, only two types are widely grown – the common snowdrop, Galanthus nivalis, and the Giant Snowdrop, Galanthus elwesii. The plants are native to Europe and the Mid-East, from the Pyrenees north to Poland and east to Russia, Turkey and Syria. They have become wildly popular in the British Isles, where there are entire gardens dedicated to snowdrop cultivation. Scotland hosted its first Snowdrop Festival in 2007 with 60 gardens participating. The most famous snowdrop garden is Colsbourne Park in the English Cotswolds, the ancestral home of plant hunter Henry John Elwes, who collected the elwessi hybrids in Turkey and introduced them into modern cultivation in the 1870s.

Galantophiles are fascinated by the subtle variations between cultivars, from the double flowers of G. ‘Flore Pleno’, to the gold dashes of ‘Lutescens”, to the broad, shiny leaves of G. ikariae, or the rare autumn blooms of G. reginae-olgae.

Snowdrops grow best in areas with a cool winter, and are hardy in zones 3-7. They take full sun to part shade, and can be grown under deciduous trees or shrubs because they will bloom before the trees leaf out in the spring. They prefer moist, humus-rich soil with good drainage, but can also tolerate an area with dry shade once established. After the plants finish flowering, their foliage should be allowed to fully die down on its own. Like other members of the Amaryllis family, snowdrops are avoided by deer and voles.

Snowdrops grow from tiny bulbs, which should be planted in the garden in fall with crocuses, daffodils, and other spring-blooming bulbs. Purchased bulbs must not be allowed to dry out, so it is best to plant them immediately or soak them overnight prior to planting. Like other small bulbs, snowdrops look best planted in clumps, so plant them 2-3” apart and 3” deep. Many gardeners recommend planting snowdrops from divided fresh clumps in the spring, after their blooms have faded, but before the foliage turns yellow. If you have any friends that grow snowdrops in their garden, this is the time to ask if they will share their plants with you.

Small size and early bloom makes snowdrops ideal flowers for rock gardens, troughs, raised beds and the edges of garden beds. You will want to plant snowdrops where you will pass them frequently or see them from your window as their charming blossoms signal the beginning of spring. They naturalize freely both by self-seeding and through bulb offsets, and can form beautiful carpets in the lawn, in the shade garden or in the shrub border.

My small collection of snowdrops began when my 8-year old son brought home a blooming clump from his friend’s house. The snowdrops were admired and left in the pot through the summer. At some point the pot was knocked over, and the snowdrops rooted themselves in the mulch under the cedar tree. The following spring they appeared there and next to our pond. Last spring I decided to move them to my circular shade bed in the driveway, because I had read that miniature bulbs can be planted around the bases of hostas. They will bloom before the hosta shoots poke out of the ground, and the emerging hosta leaves will hide the snowdrops’ yellowing foliage in May. As with any small bulbs, however, you never manage to remove the whole clump, so this year I have snowdrops popping up in a number of places. I can barely wait until I am 80 and the entire garden is white with snowdrop blooms in early March.

To start your own collection of Galanthus varieties, visit brentandbeckybulbs.com and vanengelen.com.

Redtwig Dogwood Offers Vibrant Winter Color

When I first began gardening, the only dogwood I knew of was our native dogwood tree, with it's spring-time show of delicate pink or white blossoms. Yet the dogwood genus contains a huge variety of plants, ranging from woodland ground covers, to shrubs, to trees that grow to forty feet. While many of these make excellent additions to the home landscape, none are more versatile than the redtwig dogwoods. These multistemmed shrubs are garden performers all year long and provide real drama in the winter landscape with their colorful branches.

There are two species of redtwig dogwoods, the Tatarian dogwood (Cornus alba) and the Redosier dogwood (Cornus sericea). Their care, cultural requirements and effect in the landscape are nearly identical. They are easily grown and transplanted, adapt well to dry or extremely moist soils, and prefer full sun to part shade. In spring, they have flat, cream-colored flower clusters that are followed by ivory or blue berries which provide food for birds. They have a rounded shape and spread by suckers or underground stolons, especially in moist soil, forming colonies with colorful stems in winter that have great ornamental appeal.

The Redosier dogwood is native to North America and is very useful in the New England designed woodland garden, where it spreads naturally in colorful swaths. It is often planted in groups in the shrub border or massed on slopes for erosion control. The Tatarian dogwood is native to northeastern Asia. In the home landscape, it is typically planted in groups, often with needled evergreens as a background for its colorful winter stems. Both dogwood types grow vigorously in Zones 3-7, but neither does well in the heat and humidity of the south. Noteworthy varieties are C. sericea 'Baileyi', which grows 6-9 feet high with foliage that turns reddish-purple in fall and has a winter stem color of dark red; and C. alba 'Bud's Yellow',which grows to 6 feet high, has reddish fall foliage and a winter stem color that is an unusual bright yellow.

All redtwig dogwoods offer multi-season interest, but there are some that add more drama to the home garden than others. I love the cultivars with variegated leaves: their bright foliage commands attention, spring through fall. In my garden, I grow two variegated C. alba cultivars. I use 'Elegantissima', which has greenish-grey leaves edged in white, to brighten up a shady spot in my shrub border. In early spring, its red stems are complemented by a nearby grouping of yellow-flowering trout lilies (Erythronium), whose green leaves are mottled with the same dark reds of the dogwood. In summer, 'Elegantissima' mingles effortlessly with ferns and other perennials, such as hosta (H. 'Winfield Blue', H. 'Shade Fanfare' and  H. 'Dream Weaver'), a small blue grass (Festuca glauca 'Boulder Blue'), coral bells (Heuchera 'Coral Dream') and epimedium.

I have grown the variegated C. alba 'Ivory Halo' in a large planter on my deck since 2008. This may be the year it gets planted out in the garden, but I am sold on its performance, beauty and adaptability as a year-round container plant. I will definitely plant another to grace my deck. Or maybe this time I'll try a new cultivar, like 'Silver & Gold', which has green and silver foliage and cheery yellow stems in winter.

Redtwig dogwoods require pruning to retain the winter effect of vivid branch color: the brightest color occurs on the newest branches. Prune out old, colorless branches that are more than 2-3 years old; cut them back close to the ground to stimulate bright new growth.

The redtwig dogwoods offer year-round beauty in the suburban landscape. They are especially valued for their vibrant winter stem colors that are stunning when framed by the snow.  Redtwig dogwoods can be purchased at many local nurseries and from online sources such as forestfarm (www.forestfarm.com).

By Joan Butler

Winterberry Holly Is A Beacon in the Garden

or brightening the winter landscape, nothing can compare with winterberry holly. Its bright red berries are a visual stoplight in garden settings and in our New England woodlands and marshes. Winterberry is a tough native shrub that adapts to a wide range of growing conditions. In the wild, it can be found thriving in wet, boggy locations but also does well in drier sites in the woodland and home garden. Typically, it reaches heights of 6-8 feet and spreads slowly by “suckering” to form small thickets. It grows in full sun to part shade, with berry production best in full sun. The profusion of shiny berries that cover its branches from fall through winter make it a stand-out anywhere it is planted. 

Winterberry holly is part of a diverse genus (Ilex) that includes evergreen and deciduous hollies. Most people are familiar with the evergreen varieties, with their spiny leaves and red berries that are staples of holiday decor and floral arrangements. The deciduous varieties are less well-known, although probably everyone has noticed them and wondered about their identity. Winterberry holly (Ilex verticillata) is the most common of the deciduous hollies. It is native from Newfoundland west to Michigan and south to Maryland and West Virginia. The summer foliage is a rich dark green. Autumn foliage is yellow and is not considered particularly showy. The berries that color up after the first frost  are the real show-stoppers here. And, as an added bonus, the berries are a nutritious food source for birds.

There is no shortage of winterberry cultivars. “Red Sprite” and “Winter Red” are particularly favored for their prolific production of large red fruits. Also popular is “Sparkleberry”, an Ilex verticillata hybrid with a heavy fruit set and smaller berries. If you want to try something different, “Winter Gold” produces berries that are a spectacular peach-salmon color. There is even a cultivar with variegated foliage, the uncommon “Sunsplash”, with leaves that are streaked with yellow.

As is typical of most hollies, male and female flowers are found on different plants and only the female plants produce berries. If you want berries, you must have both sexes present within a distance of 50 feet of each other; one male will fertilize 6-7 females. The male must bloom at the same time as the female. Common male pollinators are “Jim Dandy”, which will fertilize “Red Sprite” and other early-flowering types, and “Southern Gentleman” which will fertilize “Winter Red”, “Winter Gold”, “Sparkleberry” and other later-flowering types.

In my garden, I grow the cultivar “Cacapon”, which I have planted in two different locations. In the mixed shrub border out back, “Cacapon” has become a six-foot tall thicket covered with red berries that I value for their winter show and contrast against the evergreens. In the front foundation plantings, it is growing as a small tree, nearly eight feet tall now, with wonderful dark grey branches and red-orange berries. Light pruning in the spring improves berry production in both locations.

If you are looking for something to brighten your winter gardens, look no further than winterberry holly. Best planted in spring and fall, winterberry can be purchased locally at many nurseries, including Weston Nurseries, and through mail order resources such as RareFind Nursery. (www.rarefindnursery.com).

By Joan Butler