PERENNIALS TO CONSIDER
Dr. Leonard Perry, Extension Professor
University of Vermont
There are so many perennials out there, literally thousands of different ones. How do you choose ones for your own garden? This can be an especially hard question for those beginning. Perhaps you should consider four choices of perennial professionals.
Each year the Perennial Plant Association, the professional organization for the commercial industry, solicits the top perennials from its members to vote on for perennial plant of the year. The top four make the ballot. These represent those that most growers and designers nationwide feel are most adaptable and worthy of more use. Four recent choices include a catmint, Lenten rose, sedum, and lady's mantle.
Walker's Low catmint (Nepeta x fassenii) provides lovely lavender-blue flower spikes in mid to late summer in the north. These flowers top the soft, gray-green leaves, which in themselves are fragrant. This hybrid cultivar is lower than its relatives, only growing to 18 inches or so high. It is also longer blooming, with flowers over a four to six week period, depending on season.
Listed as hardy to USDA zone 5, Walker's Low has proven hardy in zone 4 (much of Vermont). Coming to us from Great Britain, this low maintenance plant is a great choice for full to part sun gardens. It resists drought well, resists deer and rabbit foraging, and grows well in average to poor soil, as long as the soil is well-drained. Use it to edge a perennial bed, massed as a ground cover, or in rock gardens.
Lenten rose (Helleborus orientalis) has been around for some time now, proving it is excellent for the shade garden. The thick, leathery, dark green leaves are palmate (divided into a palm hand shape). They persist through the year, including winter, so may come out looking a bit battered in the spring in our northern climates.
In late spring, during the Lent season (hence the name), the flowers emerge and hang down. They vary from white to pink to dark plum, and are two to three inches across. Since the showy parts are actually sepals (the parts that surround the flower petals), they last for a couple months.
There have been many hybrids developed, but this species remains the hardiest and most durable. Hardy to USDA zone 4, this native originally of Greece and Asia Minor thrives in average to slightly organic soil. It too resists feeding by deer and rabbits.
Matrona sedum comes to us from Germany. The cultivar name "matrone" in German means "lady of well rounded form", which gives a clue to its habit. The clump can reach 24 inches tall, and is very uniform and vase shaped. This is topped with large pink flower clusters in late summer which attract butterflies. Don't cut these back after bloom, as they add fall and winter interest.
Matrona is sun-loving as most other sedums, quite hardy, but differs with its rose-edged gray-green leaves, and its dark burgundy stems. This low maintenance perennial resists drought, does well in average soil, and is striking in small groups in the perennial border.
Lady's mantle (Alchemilla mollis) is one of my favorite perennials, and got my top vote! Native to Asia Minor, it has been around for years in gardens, but still deserves wider use. This plant was in fact used for centuries for its reputed healing powers, the genus name coming from its popularity with alchemists.
The rounded, velvety leaves catch water or dew into jewel-like beads that dance across the leaves. Sprays of tiny, star-shaped chartreuse to yellow flowers cover the leaves in early summer for quite some time. This color blends with most others in the garden.
The leaves form a mound about one foot high and foot or two across. It can be grown in the shade, but does best in sun in northern gardens where summers are cool and not too humid. I use it along the front of a perennial border, but it is equally effective in masses as a groundcover. It prefers a soil with some organic matter that is moist, yet well-drained. This low maintenance plant lasts for years.