The old fashioned ‘Jacobs Ladder’, P. coeruleum is short lived and can be a nuisance from self seeding. P. foliosissimum is long lived and very long flowering with no nuisance value. The lavender bluecome in heads above 2’/i feet erect and leafy plants and have been known to remain in flower from late May to September. Polemoniums are not fussy as to soil and there are two dwarf May-June flowering varieties in P. ‘Blue Pearl’ and P. ‘Sapphire’, the latter being the taller at 18 inches. P. ‘Pink Beauty’ is slightly bronzy leaved and has pinkish mauve on low bushy growth, 15 inches high from June to August. Polemoniums have fibrous and are easy to divide in spring.
The need to divide comes once the plant is seen to be producing fewer flowers though the clump has become large and inclined to sit on the ground rather than being in it at the original depth. This applies less to P’. foliosissimum’ than to the others, which may well need dividing and replanting more deeply after about three years. There are several clump forming subjects which tend to grow out of the ground when they become old and it is a matter of observation when this needs doing, with the symptoms mentioned above in mind.