Last year I posted about Impatiens scabrida, an annual species that popped up in a pot of another plant I had bought. I welcomed the interloper with the caveat that it might be a ‘spreader’. I admired the flowers and of the two plants, one was planted out in a shady spot by the back door. The other was kept in a pot and flung a few seeds round the greenhouse but the resultant seedlings were not kept when I discovered a mass of seedlings in the garden this spring.

So this is a hardy annual. Although the mature plants ‘melt’ at the first frosts of autumn, the seedlings are more resistant to cold. I worried when the seedlings appeared in March. The large cotyledons made the seedlings easy to identify and I was worried when frosts threatened to kill them. But they are made of sterner stuff and, somehow, the tiny seedlings are able to withstand frost. How this anomalous behaviour is possible is a mystery to me but, after remaining small for months, as soon as temperatures rose they grew strongly and rain a week ago resulted in another burst of growth and flowering has begun, much to the delight of the local bumblebees.

One of the reasons why Himalayan balsam (I. glandulifera) is criticised by those environmentalists that wage war on it is that it is so loved by bees that other (native) plants risk not being pollinated. I find this strange and unlikely and an odd reason to want to eradicate it (though I accept that it is an aggressive species that crowds out natives). I do actually have a clump of this species that appeared from nowhere though there is a clump by a river down the road, a mile away.

But back to I. scabrida. I am happy to have it in the garden and I think my garden is dry enough to prevent its rampant spread. Even so, in one year, it has spread from one, nurtured, plant to a clump more than a metre across with several outliers and I will have to be strict with seedling control next spring.

impatiens scabrida