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Credit: Flickr | venkane

A diverse family of old-fashioned favourites includes several summer-bloomers ideal for B.C. gardens

The Malvaceae (mallow) family has always held a soft spot in my heart, as it conjures up misty visions of old-fashioned cottage gardens ablaze with powdery pink blooms, like those I visited when I was very young. This diverse family of plants includes several summer-blooming beauties perfect for British Columbia gardens. From her delightful garden at Barnsley in Gloucestershire, England, the late Rosemary Verey introduced Lavatera 'Barnsley' to the gardening world just over a decade and a half ago. It caused quite a stir, as the latest, boldest member of the Malvaceae family. This wide-ranging family consists mostly of herbs and small shrubs, including plants as diverse as the hollyhock (Alcea), the tropical hibiscus (Hibiscus) and the cotton plant (Gossypium). In British Columbia, we are fortunate to be able to welcome several species from the mallow clan into our gardens, including my personal favourites - marsh mallow, checkerbloom, hollyhock and, of course, Verey's wonderful 'Barnsley.' Lavatera 'Barnsley' is a sport of Lavatera thuringiaca (tree lavatera), which is native to central and southeastern Europe. 'Barnsley' is a particularly showy, somewhat tender subshrub that tends to be almost evergreen in the mild winters we've experienced on the coast over the past few years, with the exception, of course, of this March's Arctic chill. Unfortunately for gardeners elsewhere in the province, 'Barnsley' is only hardy in zones 7 to 9. 'Barnsley' reaches a height of two metres or more, and has light, airy branches that float on the summer breezes, covered with a myriad of pale-pink flowers with red centres. It is so pale that its colouring is sometimes simply referred to as white. Its foliage is a pleasing grey-green shade that complements the flowers well, and its leaves are palmate with three to five lobes. At the UBC Botanical Garden, 'Barnsley' is used in our perennial border as a bold focal point giving height to the pink and purple section of the border. It should be noted that this lavatera definitely needs full sun. A hungry plant, it requires a mulching of well-rotted manure each spring to a depth of 10 centimetres over the entire root area. I grow it in a pot at home on my roof garden. Because my deck faces north, I don't trust the winters to preserve my lavatera, so I always prune it right back to about 15 centimetres in late October or early November and put it in my folding cold frame. It is in a large pot 45 centimetres in diameter and about the same depth. It is such a vigorous grower during the height of summer that twice-daily waterings are sometimes required. And it definitely needs a daily feeding of a few drops of either fish fertilizer or 20-20-20 added to the water. One last word about L. 'Barnsley': because it is a sport, it has a tendency to revert to its original purple/pink-flowered form. There are of course quite a few annual members of this family, the best-known likely being Lavatera trimestris. Popular with prairie gardeners, this is an excellent choice for Interior B.C. gardens where the summer days get much hotter than on the coast. L. trimestris comes in a colour range of white through pink, and given summer warmth, it can reach a height of 60 centimetres or so. The 'Mont Rose' cultivar shown on the cover is one of my top picks.

Alcea roseaAlcea rosea

Another of my favourite mallows is the marsh mallow (Althaea officinalis). As you can surmise from its name, its roots once provided the original flavouring of those delicious marshmallows we love to toast over a campfire. This plant is much hardier than 'Barnsley,' as its natural range is from central to eastern Europe, making it hardy from zone 3 to 9. I wouldn't refer to the marsh mallow as a showy plant but rather a textural plant, which makes it a good addition to a mixed flower border, especially if you favour the cottage-garden look. It is a tall, erect perennial with individual branches reaching two metres in height. There are usually several branches or shoots per plant. Its velvety leaves and stems are lovely to the touch. Each leaf grows up to 15 centimetres in length, with typically three to five lobes, and the leaves are alternately arranged up the stem. Midsummer through late fall, each leaf axle bears clusters of three to five white or pale-pink flowers with pinkish stamens. Marsh mallow has many medicinal uses, including its use in treatments for bronchitis and asthma. My good friend Elaine Stevens has a lovely clump of this plant in her medicinal home garden in Vancouver. But hardy marsh mallow would also be equally at home in northern and interior gardens. In the latter, it probably would be happier in a location where it gets morning sun and afternoon shade, to allow it a reprieve from the intense heat of the summer sun. I'm sure many of you recall from your youth another delightful old-fashioned Malvaceae family member. Hollyhocks (Alcea rosea) always remind me of my own childhood, as a favourite aunt of mine grew them in her garden. She also had a swing for her nieces and nephews to play on and we used to see if we could swing higher than the height of the hollyhocks. The hollyhock is often referred to as a perennial but usually performs more as a biennial, meaning it self-sows, forming a nice clump of foliage the first season followed by flowering stems the next season. Again, this is an extremely hardy plant for zones 3 to 9. Hollyhock's basal light-green leaves are rounded and just slightly lobed, measuring up to 15 centimetres in diameter. Its flower stems reach up to 2.5 metres bearing large single or double flowers all the way up the stem, which is actually a large raceme. Its flowers range in colour, including purple, pink, white and yellow. Each flower grows up to 10 centimetres across with pale-yellow anthers forming a protruding cluster in the centre. On the coast, hollyhocks are a challenge to cultivate because they are susceptible to the fungal disease known as rust. You can keep this problem at bay by hand-weeding any groundsel, which is a common annual weed that acts as the host plant for this rust. However, those of you living in the Okanagan may have much better luck with hollyhocks because of the drier air in your region. Last but not least, a forgotten old perennial member of the mallow family is Sidalcea malviflora 'Rose Queen' (checkerbloom), an erect perennial with kidney-shaped narrowly lobed basal leaves and more deeply lobed stem leaves. Early to midsummer it produces racemes of funnel-shaped rose-pink blooms about five centimetres across. The edges of the petals are quite deeply lobed. The overall height of this long-flowering and self-supporting perennial is 1.2 metres, and because it is a strong grower, it doesn't need extra staking. Quite widespread in its hardiness, it ranges from zones 5 through 10. With a grand total of about 1,000 species in the Malvaceae family, you may find it difficult to choose a favourite. Try one of my picks, and you just may discover that growing a mallow in your garden can be a marvellous experience. The following plants are hardy up to the zone number indicated:

  • checkerbloom (Sidalcea malviflora 'Rose Queen') - zone 5
  • hollyhock (Alcea rosea) - zone 3
  • mallow (Lavatera 'Barnsley') - zone 7
  • marsh mallow (Althaea officinalis) - zone 3
David Tarrant of the UBC Botanical Garden is a well-known gardening expert, author, and host of Canadian Gardener on CBC television.