Guide to growing Jacob's Ladder - Polemonium
Polemonium are hardy perennials that range in height from 15 to 90cm.
They bloom from the end of spring to summer with blue, yellow, pink or white cup shaped flowers.
One of the common names for Polemonium is Jacob's Ladder.
How to grow Jacob's Ladder
The seeds of Jacob's ladder can be sown outdoors at the start of spring or autumn; once sown lightly cover the seed. The plants should have a spacing of about 20 to 30cm (small Polemonium species) or 45 to 60cm (larger Polemonium varieties). Jacob's ladder should ideally be grown in a partially shaded part of the garden that as a rich, moist soil that is kept cool and well drained, and has a pH of 5 to 8.
If you plan to first grow Jacob's ladder indoors then start about two months in advance. It should take about three or four weeks for the Jacob's ladder seeds to germinate at a temperature of 21 degrees centigrade. Once ready the young plants should be transplanted into the garden either at the start of autumn or just before the last frost of spring.
Caring for Jacob's ladder - Polemonium
Jacob's ladder and other Polemonium species are fairly easy to care for; they like moist soil so water frequently. The soil should be kept cool, so it is best to top dress the soil with leaf mold in the spring. Once flowering has finished cut the flowering shoots back to ground level. If you require more Polemonium plants then they can be propagated by carefully division in the spring, or allow them to self and set seed in situ.