Just as vegetables and garden plants have their preferences, so do wild flowers and weeds.
Most of this page comes from an old book I really enjoy reading, Mr Newsham's The Horticultural Note-Book (1937). What can I say about it - except to wonder at the man's observation (and that of generations before him), and fear for the number of these plants now in danger. Oh, and try to figure which is the more valuable and magical - knowledge of these plants, or understanding the weedkiller labels in the local garden centre!
OK, I enjoy discovering this kind of knowledge - but there is a practical caveat; don't jump too fast to conclusions. Make a judgement on the overall balance of weeds, not the odd single specimen.
Mr Newsham uses Latin names - there is a fascinating resource for identifying these plants, on BioImages - a Virtual Field-Guide (UK). The photos are brilliant - but no substitute for a good flower-book.
For an up-to-date view on the topic, read this article. It's a Canadian website, so some of the weed names are unfamiliar - and some of my weeds don't figure at all; for all that, an interesting read.
From The Horticultural Note-Book (1937)
Plants which favour particular soils
- Stinging Nettle (Urtica dioica), Chickweed (Stellaria media), Cock's Foot (a grass) (Dactylis glomerata), and Rough Meadow-Grass (Poa trivialis) indicate a fertile soil. Now aren't you glad you have loads of chickweed and nettles?
- Brooklime, a speedwell which likes wet places, (Veronica beccabunga), Marsh Foxtail (Alopecurus geniculatus), one of the rushes (Juncus conglomeratus), and a meadow-grass (Poa aquatica) indicate a wet fertile soil.
- Heath Rush (Juncus squarrosus), Common Butterwort (Pinguicula vulgaris), Lesser Spearwort (Ranunculus flammula), and Broad-leaved Willowherb (Epilobium tetragonum renamed to to E montanum?) indicate a wet infertile soil.
- Wild Thyme (Thymus serpyllum), Lady's Bedstraw (Galium verum), Heath Bedstraw (Galium saxatile), and a Clover or Trefoil (which I haven't traced) (Trifolium arfena) indicate a dry soil.
- Heathers (Erica), Bell Heather or Ling (Calluna vulgaris), and Tormentil (Potentilla erecta) indicate a dry peaty soil.
- (Sphagnum mosses), and Round-Leaved Sundew (Drosera rotundifolia) indicate a wet peaty soil.
- A Sandwort (Arenaria rubra), Spring Speedwell (an endangered species - I wonder if that was true back in 1937?) (Veronica verna), and one of the Campions (Silene angelica) indicate a sandy soil.
- Clustered Bellflower (Campanula glomerata), Spiked Speedwell (Veronica spicata - similar to the Germander Speedwell), a Sainfoin(Onobrychis sativa), wild Catmint (I'm guessing! - Nepeta major) indicate a chalky soil.
- Coltsfoot (Tussilago farfara), Silverweed (Potentilla anserina), Hoary Cinquefoil (Potentilla argentea), and one of the Bird's Foot Trefoils (Lotus major) indicate a clay soil.
Plants which indicate Barren Soils (a selection from Mr Newsham's lists).
- Any of the Sedges (Carex spp) and most of the Rushes (Juncus spp) indicate boggy ground;
- Thistles (Carduus spp) indicate waste ground;
- Yellow Goosegrass (Galium verum) indicates dry, hilly ground;
- Ground Ivy (Glechoma hederacea) indicates shady ground;
- Coltsfoot (Tussilago farfara) indicates stiff, clayey soil;
- Common Cudweed (Gnaphalium germanicum) indicates barren ground;