Europe has contributed many weeds to Canada that challenge the patience and the joints of gardeners - buttercups, for instance. At this time of year, Ranunculus repens, the creeping buttercup, especially comes to mind.
Aside from small, bright yellow flowers, it's a difficult plant to love. It creeps with long runners down pots, across concrete and over garden edges. When it finds soil creeping buttercup stretches up to 60 centimetres and seeds all over.
The Field Buttercup (Ranunculus acris) looks similar but bigger. This one reaches one metre tall. Both can kill incautious grazing animals and are reputed to rob the soil of potassium and poison nitrogen-fixing bacteria. Both also turn into a thick, densely rooted mat if allowed to mature.
When removing them at that stage, it's useful to probe the rootballs carefully because small spring bulbs easily hide within those root masses. When the area is cleared, millions of weed seeds will have been liberated.
That's why it's useful after removing weeds from flower beds to mulch immediately with com-posted bark, mushroom manure or commercial compost. It won't smother weeds forever but will give you some weed-free months, or even a year or two.
A very long-neglected buttercup patch needs tougher handling. It may be necessary to move out any precious plants and cover the area with black plastic for a year or so. Buttercups love moisture and light. Dryness and dark is fatal to them.
The themes of moisture and greedy feeding habits run through many members of the buttercup (Ranunculus) family. These include thalictrum, clematis, anemones, aquilegias, delphiniums, hellebores, delphiniums, celandines and aconitum.
Many are extremely poisonous. Hellebore seed, for instance, can burn skin. But many have stunningly beautiful flowers and, like butter-cups, an aptitude for survival.
Once you know that something is basically a buttercup, it's easier to treat it in ways that make it happy - and also clue into what bad habits it might have.
For instance, aquilegias, hellebores and celandines are all spreaders and seeders. All love rich feeding and (although none of them will grow in a swamp) all respond very well to moist soil.
Clematis also love rich feeding and moisture and though it doesn't spread as an individual plant, it seeds so enthusiastically that some types have a reputation for invasiveness.
Noticing the kind of root and the type of leaf gives you even more information about variations. For instance, bulbs and fat tuberous roots are a storage place for food. Plants with this type of root can be forgiving after disturbance because they have enough nourishment stored up to trigger growth again.
Pulsatilla vulgaris (formerly Anemone pulsatilla) has a finely dissected leaf and a deep taproot. It's a prairie anemone which flowers in the moisture of snow melt then hunkers down for a prairie summer drawing moisture from deep-down and resisting moisture loss with a wiry leaf.
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News flash: A self-guided tour of 14 gardens on Vancouver's East Side and West Side takes place 10 a.m. to 4 p.m. on June 22 and 23. Tickets are $30 and good for both days. Proceeds to benefit Heritage Vancouver Society. For tickets and more information, go to heritagevancouver.org.
Anne Marrison is happy to answer garden questions. Send them to amarrison@shaw.ca.
