We‘re past mid-summer and the erratic spring weather that overstayed its welcome has been replaced by a spell of high temperatures and traditional thunderstorms. All of the lovely rainwater is too good to waste so I‘ve somewhat belatedly added water butts to the down pipes on the greenhouse. There‘s a range of designs on the market but whichever you choose remember they should be raised high enough for the watering can to fit under the tap. Most manufacturers provide purpose built stands though timber or a stack of slabs are useful alternatives; stock bricks should be avoided as they eventually crumble. I‘m convinced that plants prefer rainwater ‘straight‘ as nature intended, it doesn‘t contain chlorine or other additives and is better for acid loving container plants like rhododendrons and camellias, even if you live in a ‘soft water‘ area.
Greenhouse plants prefer their drinks tepid, so a rotation of several watering cans allows the water to warm under glass for at least 24 hours before use.
Tender plants have now settled into their summer routine. I bought some wonderful pelargoniums last year. They‘re not the traditional bright colours but have sumptuous flowers for a regal display. ‘Morwenna‘ is a dark, almost black flowered double regal pelargonium flowering from April until October while ‘Mystery‘ a rich, ember red has a dark splash in the centre. In the green house is an exquisite species called Pelargonium triste whose tiara of creamy-yellow flowers with purple blotches are spicily fragrant at night. Unusually, it is deciduous, so watering is reduced in autumn as the leaves die back. Pelargaoniums grow happily in a free draining compost of 50:50 John Innes no 2 and multipurpose compost adding about 1/3 sharp sand or grit to improve the drainage as they dislike being waterlogged! Feed every two weeks during the growing season with high potash tomato fertiliser for an abundance of flowers and remove the flower-heads once they have finished flowering. They vie for a place in my heart with one of the most stunning plants that I‘ve ever seen, Agapanthus ‘Back in Black‘ which should be more freely available in 2006. It‘s caused a sensation in Italy and gardeners in USA are clamouring for its beauty. It has dark agapanthus blue flowers but what makes it so extraordinary are the blue flower heads, seed capsules and stems which are such a deep blue it‘s almost black; the camera struggles to capture its beauty!
My prediction is that ‘Back in Black‘ will sweep through the gardening world causing a sensation similar to Verbascum ‘Helen Johnson‘. It is growing in a container in a mix of John Innes no 2 and multipurpose compost and will be over wintered in the glasshouse, in the hope that next year it produces even more flowers. Agapanthus in containers flower better when slightly pot bound, so mine will be suffering for its art for at least another two years!