Lobelia Erinus

Lobelia Erinus - The dwarf section of annual Lobelia is one of the most important, being much used among half-hardy plants. The chief points to start with are good soil and well-grown established plants. The soil should be light and rich, and rest on a dry bottom perfectly drained. On a porous bottom it may be plentifully watered during a dry time in summer without fear of injuring the roots. The roots cannot make way, nor can the plants thrive in a strong adhesive soil of clay or heavy loam, and if the soil be heavy, it must be lightened by a plentiful addition of leaf-mould, sand, or peat. This Lobelia thrives admirably in equal parts of sandy loam and leaf-mould, with sharp sand to keep it open. A slight mulching of one-year-old sifted hot-bed manure will be found useful for keeping out the drought and nourishing the roots through a dry season. One of the difficulties in carrying dwarf Lobelias in full beauty through the season is the freedom with which they seed, and the moment the flowers fade they should be picked off every week throughout the season. Dwarf Lobelias may be propagated by seeds or cuttings. For ensuring stock for propagating in spring, a batch of cuttings should be rooted in August from plants cut back a month earlier. Or these cut-back plants may be earthed up and later pulled to pieces and pricked out in boxes of sandy soil. These youthful examples are infinitely superior to worn-out lifted stock, and yield quantities of vigorous cuttings for February and March propagation. The cuttings should be potted by the end of May, and treated in the same way as seedlings.

L. Erinus is divided into three sections—viz., compacta, of which there is a white form; speciosa, of which the best are Blue Stone, Ebor, Blue Beauty, Emperor William, Blue King, Lustrous, Brilliant; ramosoides; pumila, of which grandiflora and magnifica are fine forms, as is also the pure white Mrs Murphy; and Paxtoniana is a lovely blue. Other dwarf Lobelias are ramosa, with large light-blue flowers, and coronopifolia, also with large blue flowers. Both are half-hardy annuals, requiring the same treatment as L. Erinus.

This Lobelia suffers from a kind of rust, which fastens on the main fleshy roots when the plants are at rest, and rots them. This disease, working as it does at a time when growth is at a standstill, is not perceived in time to be checked, and makes its appearance in November, especially if the weather be wet. The plants should then be carefully taken up, reserving as much of the roots as possible, the soil being shaken off, and the roots well washed. The disease will be readily discovered by its rusty-looking spots, which must be cut out with a sharp knife, as the least portion will suffice to destroy the plant. After the plants are examined they may be potted or laid in a frame in some free sandy soil, and very fine specimens may be obtained by potting and plunging in a slight bottom-heat, keeping the top quite cool. In about a fortnight they will have made fresh fibre, and all danger will be past. They may then be kept in a cold frame during the winter, and planted out where desired in spring. The bottom-heat, however, is not indispensable; for they will succeed if carefully and sparingly watered after potting. All the plants of the fulgens group show their great beauty only on peaty or deep leafy and moist soils; often on loamy soils the growth is short and weak, the flowers poor, and under such conditions they may not be worth growing.