Tanacetum Species, Wild Tansy, Rayed Tansy, Tansy Daisy, White-flowered Tansy

My garden is currently in Hope, British Columbia, Canada. I was given this plant by an experienced horticulturalist and garden designer. ...Read MoreThe name tag was Chrysanthemum macrophyllum. I was advised that it was grown extensively for the foliage which attains large size and I could cut out the flowering stems to further this. In the first year the plant growth confirmed that description, at that time grown in heavy clay soil in Cloverdale British Columbia with large amounts of steer manure added. I did not cut out the flower stems but the leaves reached 12"-14" in length, and the flowering stems reached 4'. The look of the foliage reminded me of Mediterranean Acanthus. I collected seed finding only a few per umbel. Those plants from seed were grown in 2gal pots in commercial growing medium. When I moved to Hope, B.C. I planted these in my present garden which is extremely fine light yellowish brown silt with little organic content. Mushroom manure is the main organic additive. The plants attained the same height as in Cloverdale but the foliage remained small, 4"-8". The following year I cut out the flowering stems as previously advised, but it was not successful in promoting large foliage. Instead, it merely denuded the plants while promoting multiple small flower heads. I moved all the plants to another part of the garden where they have flourished, expanding in the root, but not to the extent that they could be called invasive. The flower heads this year are 4"-6" and very dense, like cauliflower. The foliage is still small as above. However, in the spring of 2010, I discovered 6-8 self seeded plants close to the old planting. I let these grow and they developed the large foliage (12"-14") I had seen in Cloverdale. They did not bloom.
At this point I concluded that since these plants seem to have heavy tap roots (or something like a tap root) which grow very deep, that confinement in the 2gal pots for a year may have stunted the plants in some way, hence the small foliage on the Hope planting. These new self seeded plants with the larger foliage had had no such confinement.
Unfortunately my Vulcan logic failed me in this regard because this year those self seeded plants are back to small foliage and tall blooms. It seems possible that their use as a foliage accent may be restricted to first year growth.
Never-the-less, this is a magnificent plant, even with the smaller foliage, with masses of cauliflower-like umbels, now growing to 5' in the older planting, and as noted by another gardener above, attractive brown seed heads throughout winter. Though the flower stems are quite stiff and do not break in the wind (we have a lot of wind, particularly in the summer) the weight of them requires my staking them to preserve the light and space for surrounding plants.

This plant spreads VERY quickly! I have the pink flowered form, and after the bloom fade it turns to a eye-pleasing brown and lasts all ...Read Morewinter. I am highly satistfied with this plant.