I have noticed that many of my recent landscape designs are definitely leaning towards an alba garden palette, with customers asking for white-flowering plants, cream variegation, and some silver foliage highlights. This design theme came to prominence in the 1930s with the creation of the ‘white garden’ at Sissinghurst by Vita Sackville-West. She in turn was heavily influenced by the work of garden designer Gertrude Jekyll who pioneered the mass planting of perennials with solitary or similar hues, including the alba garden. So, I thought I would inspire you with a month-by-month revue of just some of the white-flowering or silver-hued perennials, shrubs, and trees at your disposal.
January
We start the season with what some gardeners consider a harbinger of spring, the pure white blossoms of Snowdrops or Galanthus nivalis. This species naturalizes very well and is usually purchased as a bulb in the fall, although forced plants are occasionally available. Bulbs should be planted as soon as possible, as they tend to dry out quickly and if a fellow gardener offers you some of their established Snowdrops, just lift clumps with greens in March and move them in place.
Joining it is the very hardy (zone 5) Erica carnea ‘Springwood White’ which often blooms from December to April with pristine flowers held over deep green foliage that matures at about 6” tall.
February
Next on our list is the Korean native Abeliophyllum distichum or White Forsythia. This hard-to-find deciduous plant bears fragrant blossoms from late February through April on a rather unruly 5’ tall shrub. It makes up for this by budding all along the stem and being an excellent cut flower.
Its companion is the shade-loving hardy Cyclamen coum, which flowers primarily from February to March. They have rounded silver-dollar-sized leaves (many with silver highlights) and are often sold in mixed flats, with the flowers ranging from near-white to deep magenta pink. The ‘whites’ are the most popular, so shop early before they get picked over.
March
Few Lily-of-the-Valley shrubs have as large pure white panicles as Pieris japonica ‘Snowdrift’. These emerge from pink buds in March and have a nice fragrance on warmer days. Expect an evergreen shrub that matures at 4-5’ tall and prefers a part sun exposure.
Another plant known for its fragrance is the Star Magnolia and the pure white Magnolia stellata ‘Royal Star’ doesn’t disappoint. It blooms before the leaves emerge from pussy-willow-like buds on a small tree that can actually be trained to bush form.
April
Witch Alder (Fothergilla major) is a relatively unknown member of the Witch Hazel family that bears honey-scented white bottlebrush flowers from April to May. It prefers a part- to full-sun exposure and also features fiery autumn foliage.
Azalea ‘Hino White Dwarf’ is much better known, as this compact evergreen shrub (2’ tall) literally smothers itself in pure white blossoms that are hard to miss in any garden.
May
With so much in bloom in May, it’s hard to choose just two but the old-fashioned Snowball bush or Viburnum opulus ‘Roseum’ is always a showstopper. This large deciduous shrub (10’ + tall) bears 3” wide spherical snowball flowers at this time and given its hardiness (zone 3), it is rarely affected by a cold winter.
My companion tree is the very showy Dogwood, Cornus kousa var. chinensis, which covers itself in starry bracts from top to bottom from May into June.
June
With the summer heat, perennials start their displays and one of the best here is the ephemeral but stunning Oriental Poppy, Papaver orientale ‘Royal Wedding’, with its large 4-6” wide papery white petals, accented with purplish-black spotting.
The compact (4’ tall) Mockorange, Philadelphus ‘Snowbelle’, will follow up with a dazzling display of pure white, citrus-scented double blooms and its zone 4 hardiness means that interior gardeners can enjoy it too.
July
The common name for my next perennial comes from the German ‘edel’ (noble) and ‘weiss’ (white), an apt description for the fuzzy silvery-white bracts borne from July through to September. Edelweiss (Leontopodium alpinum) also features grey-green foliage, which compliments the alba garden but requires near-perfect drainage to thrive.
My companion piece is the compact Oriental Lily ‘Sunny Okinawa’ which flowers later than most, bearing pure white flowers over dark green foliage at a height of about 18” tall. It also works well as a container specimen.
August
While the ongoing heat causes some perennials to go summer dormant, others like Iberis ‘Summer Snowdrift’ seem to thrive on it, smothering themselves in crystalline blossoms from mid-spring until late summer. While floriferous, it is a bit more tender than most Candytuft plants at zone 7.
Another heat-lover is the Nile Lily or Agapanthus which does come in alba forms such as ‘Galaxy White’. Blooming from midsummer to fall, this cultivar is hardier than most (zone 6) and really loves being grown in containers.
September
The cooler fall weather brings out the buds of the Japanese Anemones, and none of these performs quite as well as ‘Honorine Jobert’. This cottage garden favourite bears 2-3” wide pure white daisies on tall wiry stems for weeks on end, but expect the plants to be a bit precocious in their growth habit.
More restrained is the ‘Alba’ form of Irish Heath (Daboecia cantabrica) which produces large urn-shaped flowers from June to October over an evergreen shrub.
October
Few vines put on such an impressive display as Sweet Autumn Clematis (C. paniculata) which smothers itself in hundreds to thousands of tiny hawthorn-scented pure-white blossoms over the entire length of its 10-20’ from September to October.
Just as durable is the landscape rose ‘Meidiland Alba’ which is continuously contoured in a succession of 3-4” wide double blooms from May, right through to frost. It is also quite compact, growing only 2’ tall by 4-5’ wide.
November
Although commonly known as winter camellias, many of the sasanqua-types start blooming in late fall. ‘White Doves’ is one of these with spectacular semi-double blooms which often envelop the deep-green foliage.
No less spectacular is the shrub-like Wormwood, Artemisia ‘Powis Castle’, which is primarily a foliage plant with intensely silver, fern-like foliage that remains evergreen in mild winters.
December
Christmas roses (Helleborus niger) are a natural choice for December as many varieties such as ‘Jacob’ are often forced into bloom a little early for our seasonal festivities. These make great additions to mixed winter planters by the front door but their permanent space should be carefully considered, as they hate constant transplanting.
Himalayan Birch (Betula jacquemontii) may seem like an unlikely option but once you have seen the pure-white bark gleaming on a sunny winter day, it seems like a natural backdrop to any alba garden.