Beautiful lilies invade the Magoebaskloof Valley

Beautiful lilies invade the Magoebaskloof Valley

The indigenous vegetation of the paradisiacal island of Magoebaskloof consists of grasslands and forests that, from the early years of human habitation, have been negatively affected by plants brought from other regions. Most of these plants were well-behaved, but some species were rooted in their genes and wanderlust and have become the invasive exotic plants they are today.

Decades ago, Lilium formosanum was imported from Taiwan as an innocent ornamental plant. Also known as Formosa lily, St. Joseph's lily, Easter lily, trumpetlily or centgosiflily, the lily has a gorgeous tart white trumpet-shaped flower, with fine maroon stripes down the tube and a stem of soft, linear leaves. Interestingly, lilies rarely become a problem in the countries to which they are imported. They are quite interested in pollinators and soil preferences. However, Lilium formosanum has been fortunate that its preferred pollinator is Agrius convolvulus, a hawk moth-like creature that is common and cosmopolitan in South Africa.

Bronwyn Egan.

In Magoebaskloof, these elegant invaders bloom from February to mid-April and can be seen along winding roadsides. Each year, the seeds spread further and further into the few remaining bits of Woodbush Granite Grassland that cling to our mountain slopes. If left unchecked, lilies can destroy the spectacle of seasonal magic created by the rich array of native plants that adorn our mountain ecosystem: our purple fields of agapanthus, masses of perfect white arum lilies, and hollows of red, yellow and red hesperantha. Dots of Kniphofias, pink Boophane Flower Wheels, blue and white Merwilla Squills and gorgeous Watsonias.

According to NEMBA legislation, L.formosanum is a Category 1b invasive plant species. It is illegal to propagate, grow or trade lilies and they should be removed and destroyed wherever possible. Unfortunately, simply uprooting plants leaves behind treacherous bulbs that maliciously sprout to form new lilies. The most effective control method is the application of herbicides (5% Hatchet (active ingredient: imazapyr) in water) on low stems, immediately after cutting and while the plant is in the active growth phase. This way the poison will reach the follicle and prevent its regrowth. The flower heads or buds and seed capsules should be cut, hidden and burned from the time the seeds are ripe even if the capsule is not on the plant.

Another beautiful exotic white lily, Lilium longiflorum, not currently listed as invasive, can be grown in the place of L.formosanum. However, because of the difficulty in distinguishing them, L. formosanum was, until recently, considered merely a variety of L. longiflorum. Better plant some colorful native bulbs or choose from the myriad of native South African plants instead. They are so valuable that their seeds are stored in refrigerated cabinets for the future!

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