Curiously enough, many enthusiastic gardeners completely neglect that comparatively small group of plants known as biennials.
True, they require a year’s growing before producing bloom, after which they are discarded.
Yet this apparent liability can be an asset since the biennials start to bloom before most perennials show much color.
Therefore, the gardener who longs for the succession of bloom can achieve it most easily by a lavish use of biennials.
After flowering, they are easily replaced with potted annuals in bloom, thus preventing any gap in the flowering schedule.
Examples Of Excellent Biennials
Canterbury Bells
Both single and double Canterbury bells have long been favorites of mine.
Their bell-like flowers in blue, white, mauve, clear pink, or rose are produced on bushy pyramidal plants 3’ or 4’ feet high.
They are spectacular plants in the garden, and the flowers usually last a full week in an arrangement.
Here in Connecticut, canterbury bells begin to bloom in the middle of June, and if faded flowers are pinched off promptly, the small bud just behind each flower will produce another bloom.
I usually enjoy Canterbury bells for 6 weeks.
Wallflowers
Two years ago, when we were in England, the lavish plantings of wall flowers, used abundantly as an under-planting for tulips were an unforgettable sight.
The air was filled with their delicious scent. Although told they could not be grown here, like most avid gardeners, I accepted the challenge and brought back a few packages of seeds.
They were a great success, so last year I bought even more.
One night, the temperature dropped to 19° degrees Fahrenheit, and two days later, it was 70° degrees Fahrenheit.
The wall flowers looked dead. In the meantime, I had ordered some glass cloches and P.M.G. ‘s (portable miniature greenhouses).
I put them over the wallflowers, and those that were covered came through and bloomed.
This year, too, I’ve planted many shrubs early, with their glass tents.
Even though this has been a tough winter, with many days of zero temperature and little snow, at this writing on February 18th, most of the wall flowers still look green.
I feel certain that anyone with a cold frame or P.M.G.’s can bring wall flowers safely through the winter.
Flowers borne on one-foot plants come in shades of scarlet, yellow, brown, orange, and pale yellow.
Since few American catalogs even list them or else include only the Siberian, which has no scent, you will probably have to order them from Sutton’s or some other English seed merchant.
Pansies
Pansies are the favorites of everyone. Yet all too often in American gardens, they lose much of their charm because they are nearly always sold in baskets of assorted colors.
Switzerland, which has long been famous for its superb pansy strains with large, long-stemmed flowers, uses them in masses of one color, and they are so much more effective planted in this manner.
A band of white pansies against one of purple, blue, or wine shades makes a truly distinctive edging.
This year, the Read pansies of England are being introduced for the first time in this country.
These are very fragrant but are only available in assorted colors.
Pansies are usually planted in August. They need abundant moisture and should be transplanted to stand 6” to 8” inches apart.
They should be covered with salt hay after the ground has frozen or transferred in the late fall to a cold frame.
Set out in April, they will produce early flowers and, if cut back severely and fertilized in June, will continue to flower during the summer.
Sweet William
Sweet william (Dianthus barbatus) is an old-fashioned plant almost indispensable for color in the early June picture.
Planted in the foreground of a border, the foot, and a half plants will be covered with blossoms in tones of rose, salmon, deep red, pink, white, or scarlet.
I prefer to use one color only and then group 3 plants in a clump at intervals throughout the garden.
Improved Foxgloves
Stately spires of foxglove or digitalis are charming candidates for the rear of a border.
The hybridizers have significantly improved color and flower form in recent years.
Instead of the usual magenta, choice colors of clear shell pink to deep rose and salmon and purple are now available.
Many are splashed with crimson, brown, or dark red spots. The pure whites are exquisite.
Instead of drooping flowers in the new hybrids, the individual florets are produced horizontally all around the stem, thus revealing the contrasting markings.
In the 1954 trials, the Royal Horticultural Society of London awarded the first-class certificate to Sutton’s Excelsior Hybrids. These are truly magnificent additions to any garden.
Hollyhock
The old-fashioned hollyhock (Althea roses), although a biennial, will usually self-sow so prodigiously that it seems almost perennial.
Double or single blooms are borne on 5’ foot plants in July and August.
A wide range of colors includes pink, rose, salmon, red, yellow, and scarlet.
When transplanting hollyhocks, move them while small because of their long tap roots. They will bloom even in locations where the soil is poor.
Two Diminutive Flowers
No one can visit England in the spring without being acutely conscious of two small flowers, neither of which are grown to any great extent here.
One is the English daisy (Bellis perennis), the other, forget-me-not or myosotis.
In England, both are so lavishly used as underplantings in tulip beds that no soil is visible.
The daisies, available in pink, deep rose, and white, are borne on small compact plants.
Forget-me-nots grow about a foot tall and produce quantities of sky-blue flowers.
They present an unforgettable spring picture using en masse as an underplanting for pink tulips.
Although they prefer damp soil, they will do very well under ordinary garden conditions.
Plant Biennial Seeds Early
Probably many of you who have greatly admired members of the biennial clan do not grow them because you have not been successful with them.
They are just as easy to grow from seed as many annuals or perennials. But timing is a great factor in success.
Except for pansies, which may be sown as late as August, most biennials should not be sown later than June.
That will give the seedlings time to develop into vigorous plants, which will bloom the following spring.
If seeds are sown as late as August, which is often advised, plants will be too small to bloom the next year.
I have had this happen, and it is discouraging to carry plants through the winter and then not have them bloom. So plan to start seed no later than the middle of June.
Even when weather conditions permit outdoor sowing, I prefer to start all seeds in a bulb pan or small flat.
Here’s how I do it:
- I fill the pan or flat with a mixture of leaf mold and soil, with a full inch of vermiculite or sifted sphagnum moss on top.
- Then, seeds are sown and covered lightly with sifted sand or sphagnum, pressed down, and watered well.
- Cover with a pane of glass or make a miniature greenhouse by sliding a polyethylene bag over the pot.
- Keep the seed bed moist but not soaking wet.
- Remove cover as soon as seeds germinate and place in a sunny spot, ensuring that tiny seedlings do not dry out.
Sometimes in summer, they will need to water twice a day and be transplanted into flats as soon as second leaves appear.
When about 2” inches high, move into the garden, preferably on a cloudy day.
Here are the steps to move them:
- Dig a hole large enough for each plant and fill the hole with water before the plant is set.
- Water flat thoroughly before the seedlings are removed.
- Then water again when the plant is set and cover each plant with a strawberry basket for several clays.
Planting Biennials For A Lovely Cutting Garden
I plant all my biennials in rows in my cutting garden. There they grow until they are moved in the spring to locations within my borders.
They do need some protection in the winter. Salt hay is excellent if placed around the crowns of the plants, as with foxgloves or canterbury bells.
I am completely sold on the P.M.G.’s mentioned earlier. This winter has certainly been a good test, and the plants under them arc coming through almost 100% percent.
I feel sure that once you grow biennials, you will never again be without them.
They fill a gap in our gardens between the early flowering spring bulbs and the later flowering perennials and annuals.