June 2012


A species well worth growing for its long flowering period. It is a tuberous-rooted sort that comes from Madagascar. The tubers appear the first year from seed and the growth above the tuber will die off that year leaving the tuber to overwinter. It produces new growth the following year. The tuber normally grows above the ground in the wild, so do not be tempted to plant it under the soil or it will rot off. These plants can easily be propated from cuttings, but then the tuber does not come back and the vegetative part will only last a year, unlike cuttings taken from Impatiens flanaganae which do produce a tuber. Therefore, the flowers of tuberosa need to be pollinated to get seed in order to produce a plant with a tuber.
The flowers are produced in abundance, close to the top of the stem in full view. They are normally pollinated by bees, but can easily be pollinated by hand. The colour of the flower is dark pink with very little variation, unlike Impatiens bicordata which has a large range of colours.
The minimum temperate in the winter should be about 10°C and you must keep the tubers dry to avoid rot. In summer it can be kept outside, but preferably in the shade. It can take high temperatures, but keep it well-watered then. Normal potting soil is fine; it does not require special mixtures, but avoid soil with a high clay content. The only problem with pests is likely to be red-spider mite and keeping the air moist will help to combat that. I hope to offer this sort next year on my list.

 

Impatiens tuberosa

Impatiens tuberosa

Impatiens tuberosa

Impatiens tuberosa

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This is a very popular plant in cultivation, because it is very easy to grow and flowers regularly throughout the year with cream-coloured flowers. The flowers are highly scented to attract moths for pollination. It is a suitable plant for hanging baskets where it will grow to 1-2 metres. It can also be grown on a trellis, but it has to be fastened up. It can best be grown in half shade, but it will tolerate some sun. Lacunosa has many variations in leaves and flowers and hence a lot of cultivar names are used for the same species.
The plant originally comes from Java, Malaysia and Thailand and therefore likes a lot of warmth (at least 20°C) to do well. It does well in the ordinary living room as long as you keep it well-watered. It is very easy to propagate from cuttings and also by seed as long as moths have access to the plant.

Hoya lacunosa

Hoya lacunosa