A taste of the exotic
Create a lush border with tropical plants, says Marie Staunton
Published 06/10/2013 | 05:00
Tropical plants can be such a draw for gardeners and some of the planting schemes in OPW gardens have included canna lily and ricinus and the very beautiful Lobelia cardinalis to get the pulse racing.
The drawback of using plants like this is a lack of space to store them over winter in the average back garden. But if you can squeeze them in somewhere, it will be well worth the effort. Even a small glasshouse, garage or shed will keep them safe over winter.
The beauty of tropical plants is the fact that you can wheel them in and out to fill a border during the summer season and everyone will think that you are a fantastic gardener. The trick is to use them in a way that they would appear in their natural environment, so it's all about creating a lush planting scheme that includes both flowering and foliage plants, to give the impression of a holiday island.
Even if a holiday on a sun-drenched island is about as far-fetched as winning the Euromillions, at least when you walk into your garden you can console yourself a bit with a few tropical plants.
The long border in the Botanic Gardens and the tropical border at Farmleigh in Dublin use this sort of lush planting during the summer to great effect. The addition of edible plants, such as Swiss chard, helps to fill out the front of the border. You can then add in pots of dahlia to complete the look.
Cannas are herbaceous perennials and die back completely in the winter. The roots look a bit like those of an Iris. In warmer countries, they would continue to produce leaves as the others die, but not here in Ireland.
In some parts of the country, you might get away with leaving them in the ground with a very thick layer of mulch to protect them. If you have the room to store them, lift them out of the ground and bring them in once the leaves have been hit by frost.
Cut the stems back to ground level, whether you are leaving them outside or taking them in. A dry garage will do grand if you want to store them over winter. They are easy enough to divide and the best time to do this is in the spring, just before they come back into growth.
The biggest problem when dividing this sort of plant is the risk of infection to the fleshy rhizome. Use a very clean, sterilised knife when you cut a section off and make sure each new section has a number of growing points on it. It's a bit like when you are cutting up a dahlia tuber – each section should have a few eyes, which is where the new growth will come from next spring.
Pot up each new piece in some compost and water a little until you see growth appearing. Once they are actively growing, you can increase the watering; remember, these are greedy feeders, so throughout the summer you will need to feed them well.
I once made the mistake when dead-heading a canna by going too far down the stem and, as a consequence, removed the side shoots that would have produced more lovely flowers. So only dead-head the flower and don't be tempted to go any further.
Lobelia cardinalis are well worth growing and will add to the lushness of a tropically inspired herbaceous border. The real beauty of this plant is its ability to flower from around June into autumn. The vivid red flowers stand out against the purple stems and the leaves can be tinged bronze. It will flower from the side stems like the canna, so be careful when dead-heading. This isn't a long-lived perennial, so take some cuttings or propagate from seed.
The leaves are dropping off the trees at a tremendous rate now and those autumnal misty mornings are part and parcel of the season. So enjoy the down time and start taking it easy. A bit like plants, we need to recharge the batteries ready for the off next spring.