Lobelias have small, round leaves and flowers up to 12mm (½") in diameter.
They come in a variety of colours and are useful subjects for window boxes, hanging baskets, planters and ground cover.
Some varieties are compact and mound to 150-200mm (6"-8") in height and spread to around 200-300mm (8"-12"), others are definite trailers an attribute well suited to hanging baskets.
They will flower all summer and autumn in slight shade but will be quite happy in a sunny site provided it is not too hot.
Keep them well watered and fed using high potash feed during the growing season.
Sow seeds of the bedding varieties on the surface of trays filled with seed compost, and germinate at a temperature of 21°C (70°F).
Prior to sowing add a teaspoonful of dry silver sand to the packet and shake the seed and sand thoroughly together, then spread on the surface of the compost.
Alternatively, place the seed and sand in a salt or pepper shaker and shake the compost onto the surface of the compost.
Add Silver sand to Packet
Sow Seed & Silver sand
onto surface of Compost
Germination should take a week to ten days.
Seedling growth can be quite slow after the germination stage so care should be taken when watering to prevent the onset of fungal diseases e.g damping off.
Prick out the seedlings in groups of three or four, (they are too small to prick out individually), and grow on at a temperature of 10°C (50°F)
A useful technique to assist pricking out is to take a leaf out of the commercial grower’s book and grow them in plug trays.
This is done by sowing the seed as described above, but as opposed to using conventional trays, use 12x12mm cell trays.
What this does is, it allows you to grow the seedlings on to a larger size prior to potting up.
When the seedlings are approximately 12mm (½”) high, prick the clumps/plugs out into 50x50mm (2"x2") cell trays.
If purchasing plugs direct from a garden centre or mail order supplier remove the tray/container on arrival from its packaging and water if dry.
Let plants stand for a day to recover from their journey, then pot on into individual 75mm (3") pots or cell trays* of multipurpose compost.
*Subject to plug size!
For example if plugs are 12mm square use the method shown above, if the plugs are much larger pot them up into pots or larger celled cell trays.
Gradually harden off the plants in a frost free cold frame until planting out time.
Plant out 150-200mm (6"-8") apart in moist fertile soil in full sun or partial shade.