Meet Mark Cullen

Canada's best known gardening personality, Mark Cullen believes that Canadians of all ages need to play more - preferably in the dirt. A best-selling author with over 400,000 books in print, Mark reaches over one million Canadians every week through various media outlets. He is Home Hardware's horticultural spokesperson and regularly contributes to various magazines, gardening shows and newsletters. With a familiar style that people can relate to, he delivers a message that is compelling, fun, informative and inspirational - all based on his organic approach to gardening. In his spare time Mark enjoys driving his Ford Model A - and of course he loves to garden.

Count Down to St. Patrick's Day

~March 14, 2012

I can enjoy a beer to celebrate St. Patrick’s Day along with the rest of the gang – but green beer! I prefer the green touch to materialize from my plant collection, the lucky Shamrock for example.

Look for Shamrocks at your garden centre, they are not just available for St. Paddy’s Day, they are an attractive and ‘lucky’ plant to have in your home at any time. They make a great windowsill plant in a sunny location where they will display their cup-shaped white, pink, red, or lavender flowers for many weeks, even months.

Truth is, Shamrocks sold this time of year are not exactly Shamrocks – they are Oxalis.

Oxalis (Wood Sorrel)
There are many plants that make up the Oxalis family, a genus of at least 850 species of annuals, perennials and shrubs, most of which are native to South Africa and tropical and South America. This plant has three types of root systems - bulbs, rhizomes or tuberous. The name, Oxalis, derived from the Greek for acid, alludes to the sharp acid taste of the leaves of many of the species. Some of these plants are hardy perennials, some tender houseplants and some are what we refer to as ‘weeds’, such as the yellow-blooming, extremely prolific variety that seems to appear from nowhere in our flowerbeds and lawns, spreading and multiplying faster than we can pull it out.

The leaves frequently comprise three leaflets, sometimes more, which fold up at night. The slender five-petaled flowers open in direct sunlight and close umbrella-like when out of the sun or in darkness. When the ripened capsules open, the seeds are ejected with great force, spreading far afield.

Most Oxalis bulbs can be forced to bloom at any time of the year. After a flowering period when the bulb stops blooming, allow it to go into dormancy for a few weeks, the leaves will yellow and die. The plant might appear to be dead, but don’t be deceived, it’s simply taking a rest. During this dormancy period, don’t water. The plant will re-awake itself and start sending out new shoots. At this time you can start watering and fertilizing again.

As with most plants there are good and bad in each family and you and I are really only interested in the attractive worthwhile plants that make us feel we have found something beautiful that no one else has yet discovered. Here are three members of the oxalis family that simply cannot be ignored.

Oxalis deppei (Wood Sorrel, Lucky Shamrock)
This is a dainty plant (bulb) originating from Mexico and grows to a height of around 20cm (8in.). This is often referred to as the ‘good luck’ plant or ‘iron cross’ and produces four green leaves, resembling a lucky four-leaf clover, and displays a burgundy splash-type marking in its centre. The upstanding flowers, which tower above the foliage, are reddish pink to rich purple.

The edible leaves have a sharp lemony taste, somewhat similar to sorrel.

Although these taste rather good in salads, it is best to err on the side of caution and not consume huge quantities at one sitting as the leaves contain oxalic acid and this could interfere with the absorption of certain nutrients into the body, such as calcium. This substance is also found in other nutritious foods such as rhubarb and spinach. The quantity of oxalic acid will be considerably reduced if the leaves are cooked. However, I imagine like me you have selected this plant for its attractive plant properties and not especially for its nutritional value.

Oxalis triangularis (Wood Sorrel)
This is another variety that is excellent for container growing. The very small rhizomes resemble small pine cones, leaves are deep purple and the flowers are delicate lavender pink. This plant makes a wonderful contrast in a container

Oxalis regnelli (Wood Sorrel)
Oxalis regnelli, also known as Oxalis rubra alba, is one of the more familiar varieties and is very similar to Oxalis triangularis. However, the three-lobed, large green leaves are deep purple on the reverse and the pretty clusters of flowers are pure white.

Why not experiment with a selection of Oxalis in a decorative container where they can blossom and complement each other with their varied leaf and flower colours? Enjoy, but beware this is a plant that might seduce you into becoming hooked on collecting Oxalis and, because they bloom so profusely, you might be tempted into seeking further varieties!