Occasionally plants introduced to gardens like their conditions so well they spread like bad weeds. One of these Campanula rapunculodis the creeping bellflower, is very troublesome in gardens in both Montana and Wyoming and probably elsewhere, although I have gathered no reports.
It has become such a problem that weed specialists in Montana want to put it on the list of noxious weeds.
The flower spikes will range from three to four feet high above a more or less basal growing plant. The nodding flowers are deep violet. The leaves are described as rough and egg shaped tapering to a point. The base leaves have long stems, while those growing along the base of the flower spikes clasp the stalk closely.
H. Clifford Cook in his book Campanulas indicates that although this plant is quite beautiful, it should be restricted to the "wildest of wild gardens." L. H. Bailey in "The Garden of Bellflowers" described the plant as a biennial. In Eurasia and North Africa this plant is apparently occasionally grown as a fall or winter vegetable. Because of a pungent, biting taste, the somewhat thickened roots and base leaves are used in salads.
Because of the hardy, thickened, persistent root system and the ability of the plant to spread quickly by root cuttings, the plant has been difficult to control and kill. In Montana it has invaded flower and vegetable gardens and has even encroached on lawns, hedge rows and shrub borders.
Efforts to control it with many commonly known weed killers have not been too successful. The Horticultural Field Station at Cheyenne, Wyoming, was successful in controlling the plant with amino triazol. One spraying according to manufacturers directions applied during an active growing period of the plant has been successful under conditions at the Cheyenne station.
This weed killer has also been highly successful in controlling poison ivy. In using the roundup weed killer spray, it is necessary to confine the spraying just to the immediate area of the plant to be controlled. The use of a low pressure and volume will confine any spray drifts. If spraying is done on a lawn, the grasses in the sprayed area will be killed, but can be reseeded in a little while afterward.
Amino triazol kills by destroying chlorophyll in the leaves of plants. Without chlorophyll, plants. are unable to manufacture their own food and soon die.