Dandelion, Taraxacum officinale

Even digital botanic gardens have weeds - in the case of mine, dandelions Taraxacum officinale agg. Dandelions are cosmopolitan weeds and long ago the European species was introduced into the United States, where it has become a major weed. Part of this plant's success can be attributed to its reproductive system, where it sets seed without the need for pollination, and its prolific seed production is coupled to an extremely effective wind-assisted seed dispersal mechanism. Back in 2007 two researchers at Purdue University in Indiana, Tamara McPeek and Xianzhong Wang, were curious to know how this plant might fare in future world where carbon dixide levels were double those of today - which is likely to occur around 2080. For the grandchildren of today's gardeners, their findings make ominous reading. The plants produced 83% more inflorescences and 32% more seeds that were larger, germinated better and established faster. Not only that, but they travelled further because their parachute of hairs (the pappus) was larger and carried the seeds further on the wind. Source: Tamara McPeek and Xianzhong Wang (2007) Reproduction of Dandelion (Taraxacum officinale) in a higher CO2 environment. WEED SCIENCE Volume: 55 Issue: 4 Pages: 334-340

Common daisy - a postscript: the Childling Daisie

This delightful variation on the common daisy, known as the Childling Daisy or Hen-and-Chicks Daisy, photographed in Durham University Botanic Garden, was first described by the Elizabethan herbalist John Gerard. In his famous herbal of 1597 he wrote "There is another pretty Daisie which differs from the first described onely in the floure, which at the sides thereof puts forth many footstalks, carrying also little double flours............ so that each stalke carrieth as it were an old one and the brood thereof; whence they have fitly termed it the childling Daisie.”

Many members of the daisy family (Compositae, also known as the Asteraceae) sometimes produce additional flower heads (capitula) from the main one, when individual florets develop abnormally but this daisy - known as Bellis perennis prolifera - is significantly different, with multiple minor flowers on branches that arise from the main flower stalk, below the central flower.

Today plant molecular biologists working at the cutting edge of science depend on being able to generate mutants of plants at will in order to study and understand the way that genes work. Our Elizabethan ancestors were equally fascinated by these unusual ‘sports’ of wild flowers and cultivated them in their gardens ....... where some are still grown as horticultural curiosities.

Common Daisy Bellis perennis

I’m not much of a fan of billiard table-perfect lawns. Striving to maintain monotonous grass in a perpetual state of arrested development seems to me to be the height of horticultural futility, especially when you consider the vast quantities of fertiliser and lawn mower fuel used and the suburban noise pollution that comes from lawnmowers. There are many more interesting and creative ways to cultivate a patch of land. Dr. Lalita Calabria has some interesting ideas over on her Adventures of a Phytochemist blog. But, if it wasn’t for mown grass, daisies would be a lot less common than they are – and I rather like daisies. They’re well-adapted to life in lawns, with rosettes of leaves pressed so close to the soil that mower blades can’t do them much damage and even it they do lose their flower heads new ones spring up very quickly, pretty much all-year-round. Daisies thrive in the open, low-diversity lawn habitat but soon go into decline if you stop mowing the grass – they can’t cope with deep shade of tall grasses.

In about a month’s time roadside strips of grass around towns and villages will be enlivened with cheerful displays of daisies – and they’ll stay like that for a week or two until the contractors arrive for the annual spring mowing. The daisies will be decapitated but close-cropping the grass like this will ensure the daisy plants' survival for the rest of the year: one of life’s little ironies.

Safflower Carthamnus tinctorius

Safflower Carthamnus tinctorius is a very ancient crop plant, cultivated at least since the time of the ancient Egyptians. The orange florets have been found sown into garlands of papyrus and cloth wrapped around the necks of mummies (including that of Tutankahmun) dated as early as 1600BC. Later the Egyptians learned to extract the dye from red- and orange-flowered varieties and used it to dye cloth, and together with indigo it remained an important dye up until the development of modern synthetic substitutes. The valuable edible oil content of safflower seed was probably discovered by the Romans. The crop has been cultivated for its oil in India for hundreds of years and by the end of the 19th. century it began to be grown elsewhere - including the United States - as a source of oil. A field crop of safflower in full bloom must be quite a sight. It develops deep roots quickly, so grows well on the falling water table in summer in Mediterranean climates and is relatively drought-tolerant. It produces two kinds of oil - polyunsaturates for soft margerines and salad oils and mono-unsaturates used for frying. More recently, ornamental varieties have been bred, not least because the florets retain their colour well when the flowers are dried - something that the ancient Egyptians discovered. The plant in the picture arrived in wild bird seed that I put out for birds in winter, and came up in the garden as a self-sown seedling.