Brian Minter: New plants that extend bloom times
Credit to Author: Stephen Snelgrove| Date: Fri, 10 Jan 2020 19:00:29 +0000
For some time now, there’s been a trend toward longer-blooming perennials. Perennial breeders have been focusing on several issues including growing more compact plants for small space gardens and containers, developing more pest and disease-tolerant varieties and keeping an eye on drought resistance as our climate changes. In recent years, the paradigm shift, however, has been about lengthening the bloom time, and 2020 is going to reveal many exciting new varieties.
Whenever I am asked to recommend long-blooming, carefree perennials, I have always suggested the invincible rudbeckias and coreopsis, the beautiful blue ‘Rozanne’ geraniums and the repeat-blooming achilleas.
There are many fine companies providing a wide range of great perennials, but Darwin Perennials in Holland, which is now owned by the Ball Corporation, has really moved the goalposts in this regard. This year they have put together one of the best collections I’ve seen of perennials that are pushing the boundaries on long-blooming colour.
In our industry, new perennials will be potted up soon for this year’s sales. It may be late April through June before they are rooted and ready to make a splash in our gardens. At first, as with anything new, all the varieties may not be readily available in all local garden stores, but they are coming, and they are well worth the search or the wait.
Yellow alyssum, along with winter aconites and early daffodils, are the first spots of yellow to show up in our gardens. Darwin has introduced a new and quite different alyssum. It’s called ‘Golden Spring’ (zone 4a). It grows low (6 to 8 inches, 15 to 20 centimetres), has smaller, neater foliage and blooms well into April and May with the largest flowers of any yellow alyssum. It also has a much more attractive look when not in flower.
The Armeria ‘Dreameria’ is excellent for rock gardens and containers. Photo: Ball Horticultural.
The old-fashioned armeria or thrift has a new addition called ‘Dreameria,’ which grows a little taller (10 to 12 inches, 25 to 30 centimetres), has a tidy habit, is very heat tolerant, and get this — these new varieties will bloom from March through October, making them ideal for rock gardens and containers. The colour range has also expanded to include bright pink, deep rose, dark salmon and a new lavender mauve. This series will change the nature and expand the use of thrift.
Blue campanulas are always a garden favourite. The cup-shaped flowers of C. ‘Delft Teacups’ and C. ‘Violet Teacups’ (zone 3a) bloom continually from late spring well into late summer. Both varieties are short (6 to 8 inches, 15 to 20 centimetres), making them excellent for border plantings. They also combine well with annuals and other perennials that bloom during this period.
Over time, wallflowers have been disappearing from modern gardens, but in zone 7 areas, the new erysimum ‘Cheers’ series will bloom from March into September. They’re a little taller (18 to 22 inches, 46 to 56 centimetres) and are far more heat tolerant. They come in traditional wallflower colours of yellow, orange and mauve, as well as a variety called ‘Sunkissed Amethyst’ that changes colour as the flowers open and mature … and yes, they have that perfume.
The Coreopsis ‘Super Star’ has the largest flower of any coreopsis. Photo: Ball Horticultural.
There are lots of different varieties of perennial coreopsis, and many of them are the backbone of summer gardens. Darwin’s new ‘Super Star’ challenges even their performances. Hardy to zone 5a and growing 14 to 16 inches (36 to 41 centimetres) tall, it blooms from March to November. It also has the largest flower of any coreopsis and yes, it has good mildew tolerance as well. If you are a big fan of the thread-leafed varieties, like the old C. ‘Zagreb’ and the new C. ‘Sylvester’, ‘Super Star’ has all the same qualities and bloom times but with flowers twice the size of all other Coreopsis verticillatas.
Achillea or yarrow always possesses the same charm as wildflowers, and the ‘New Vintage’ series (zone 4a) really pushes the boundaries of bloom time. From April into September, these varieties bloom in colours of red, rose, white and violet and grow only 12 to 14 inches (30 to 36 centimetres) in height. Their flowers do not fade out as they mature like so many other strains. A sister series, called ‘Milly Rock’ (zone 5a), with their long-blooming and mounding habits, are strong candidates for containers. Both series have great disease tolerance.
Shasta daisies are old-fashioned garden favourites, but most varieties perform well for just a month or two. An older seedling leucanthemum, called L. ‘Becky’ (zone 5a), is the exception with a bloom time from June through August. It’s one of the tall daisy forms and has a good following. Well, a new compact leucanthemum (12 to 18 inches, 30 to 46 centimetres), called ‘Spellbook Lumos’ (zone 5a), is a fade-resistant, true yellow variety that stretches this family’s bloom time from April to August! Wow!
There’s no question that English lavender, Lavandula angustifolia, is the world’s favourite lavender, but we all wish its bloom time could be stretched out — both for our benefit and for our pollinators. Lavandula ‘Annet’ changes all that. Hardy to zone 5a and growing 16 to 18 inches (41 to 46 centimetres) tall, its strong, stiff stems bloom with very large, deep lavender flowers from April to September. The older and shorter ‘Superblue’ (10 to 12 inches, 25 to 30 centimetres) also provides this long flowering period. You might want to add both of these lavenders to your garden.
The Salvia ‘Blue Marvel’ blooms from March to September. Photo: Ball Horticultural.
In Europe, salvia is now challenging lavender in popularity. A couple of new larger-flowering varieties worth checking out are ‘Blue By You’ (zone 4b) which grows 20 to 22 inches (51 to 56 centimetres) and the more compact ‘Blue Marvel’ (zone 4a) which grows 10 to 12 inches (25 to 30 centimetres). Both bloom from March to September. Although more correctly identified as repeat bloomers, they are seldom without colour.
These varieties are but a few of the many great new perennials that have been bred to give gardens more and longer colour. Remember, however, they need to become well established before they can live up to their billing, and each climatic area will achieve somewhat varied results. They have all been well vetted, and they offer some exciting new garden opportunities.