University of Vermont
Department of Plant and Soil Science

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PERENNIAL PLANT FEATURE: AVENS

Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont
 
Avens are hardy perennials, often known by their scientific genus name (Geum).  Although uncommon, this perennial is easy to grow, has few pests or problems, and provides numerous small flowers in late spring into early summer.  Depending on selection, flowers may be in variations of yellow to gold, orange, or red. 

It’s no surprise that with rose-like flowers, this perennial is in the rose family.  Flowers are held on wiry stems above the foliage and, depending on species and cultivar (cultivated variety), may be upward-, outward-, or down-facing.  The lower compact rosettes of hairy leaves are generally under one foot high, while the flower stems may reach two feet high. Leaf shapes can be quite variable and, in mild winters and climates, may be semi-evergreen or evergreen. Occasionally you may find some minor powdery mildew on leaves, primarily with water avens (G. rivale), alpine avens (G. montanum), and wood avens (G. urbanum).

Fruits develop after the flowers and have long feathery tails on seeds, resembling puffs of smoke above the plants.  They’re particularly attractive in prairie smoke avens (G. triflorum) and alpine avens.

In the cooler North, avens grow best in full sun and can tolerate part shade (four to six hours of direct sun daily).  In warmer climates, they prefer afternoon shade.  Avens prefer moist, well-drained soils and do not tolerate wet soils, particularly during winter.  The ideal soil will vary with species, as they originally come from various areas of Europe, Asia, Africa, and the Americas. The prairie smoke avens, for instance, is native to dry prairies and rocky places.   The Chilean avens (G. chiloense) and scarlet avens (G. coccineum) are native to woodlands with moist, nutrient-rich soils. Generally, avens need minimal fertility.

If leaves are brown after winter, or get scorched brown from drought, merely prune them off and new ones will appear.  If flowering stems appear unsightly after bloom, prune these off.  This also will help prevent reseeding, if this is a concern, from some selections and perhaps such “deadheading” will encourage reblooming in late summer.

Some species and hybrids are short-lived—only growing a few years—including the Chilean and scarlet geum and their cultivars.  For these, divide plants every year or two (“crown division”) to keep plants vigorous.  Division also is the means to get new, identical plants.  While some, such as ‘Mrs. Bradshaw’ and ‘Lady Stratheden,’ are grown from seeds, many cultivars grown from seeds may not “come true to type.”

Since avens are low, compared to many perennials, they’re best used in masses or along the front of a border or walk.  Their warm colors contrast nicely with blues and purples, such as from perennial salvias or sages, with many perennial geraniums and catmints.  Contrast the flowers with dark-leaved coralbells (Heuchera), or interplant for a more bold effect with gold- and orange-leaved coralbells.  Avens combine well, too, with ornamental grasses such as prairie dropseed (Sporobolus heterolepis) and little bluestem (Schizachyrium scoparium). Many avens work well in container plantings, and the prairie smoke avens is good for rock gardens.

In trials by Richard Hawke at the Chicago Botanic Garden, 49 different avens were compared, with 46 living at least two years and most living for at least four years.  Of all those tested, 60 percent were rated either good to excellent. 

Four of the avens in the Chicago trials received five-star excellent ratings.  Prairie smoke avens (G. triflorum) has nodding, white to rosy-pink flowers held about 18 inches high.  The white petals are actually hidden beneath the rosy-pink bracts (modified leaves).  In Chicago, this avens bloomed over a long period—from early May to early July.  The rosette of leaves, from which the flowering stems arose, was 10 inches high and 20 inches wide.

‘Sangria’ avens has upward-facing, semi-double scarlet flowers held about 30 inches high and blooming from early June to early July.  The leaf rosette of this avens was 16 inches high and 30 inches wide. This is part of the Cocktail Series of avens, bred by nurseryman Brent Horvath of Intrinsic Perennial Gardens in Hebron, Illinois. This series features bold colors such as with ‘Sangria’, and softer colors as with another top-rated avens—‘Mai Tai’.  Flowers of this one open as a muted red, turning apricot on burgundy stems.  The outward-facing, semi-double Flowers bloomed in Chicago from late April until early June.  While flower stems of ‘Mai Tai’ were 24 inches tall, the rounded mound of leaves was 10 inches tall and 24 inches wide.   

‘Totally Tangerine’ (which you may find as ‘Tim’s Tangerine’) also has upward-facing, semi-double flowers on stems to about 30 inches high.  The orange sterile flowers bloom over a long period, from late May to mid-July.  The leaf rosette reaches 10 inches high and about 20 inches wide.  This is one of my favorite perennials, which has grown well for me in Vermont.

Several avens were either quite short-lived, or not hardy, in the Chicago trials and so are recommended to be treated as annuals.  These included ‘Blazing Sunset’, the popular ‘Mrs. Bradshaw’ and ‘Lady Stratheden’, ‘Double Bloody Mary’, and wood avens (G. urbanum).   The latter, too, was one of the least attractive, had severe mildew some years on leaves, and reseeded to the point of being weedy.

You can learn how the many other good avens performed from an online bulletin.  There are many other bulletins, too, on other perennial trials at the Chicago Botanic Garden by Richard Hawke (www.chicagobotanic.org/research/ornamental_plant_research/plant_evaluation).

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