This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In the Gardener's Monthly, just at hand, you ask if there is anything better than lobelia for a blue bedding plant. There is. The dwarf blue Ageratums are far ahead of it for free flowering during the hot weather. I have three varieties of ageratums, any of which are very suitable for forming ribbon lines with achyranthus and cen-taurea. One, named J. Douglas, will do well if planted between the achyranthus and centaurea. Another I have under the name of Countess of Stair is a much dwarfer, but of as free blooming habit, as the one mentioned ; the most suitable place for it is in front of the centaurea.
These ageratums are so much ahead of the old late-growing kind,which does not flower until late in the fall, in the flowering qualities, and dwarf-ness of habit, that it gives them much more value as bedding plants. They begin to flower just as soon as set out; in fact they are never out of bloom from the time they leave the cutting bench until the frost catches them in the fall. It is difficult getting cuttings off them free of flower buds.
The lobelia does well in a partially shaded position, or when it is newly set out; but when the dry, hot weather sets in it quits flowering, and does not make a very attractive plant again until late in the fall, when it begins to flower, and continues until frost. I tested last summer in several positions the ageratum and lobelia, alongside of each other, but the ageratum in every position was far ahead of the lobelia.