Jacob's Ladder, polemonium caeruleum is a perennial that the dogs have repeatedly pummelled into non-existence in my garden. I haven't given up on it just yet, in fact last summer I found a new spot for it in the front garden, where the dogs rarely tread.
To my mind, you want to think about adding Jacob's Ladder to your garden for the foliage.
On their own, the flowers are small and a bit unspectacular. (This is Polemonium caeruleum 'Stairway to Heaven' in flower above).
The single flower wispers. A grouping of plants covered with flowerbuds and softly colored blooms speaks up for itself and commands some attention.
To make any sort of impactful display, I think you need to plan on a cluster of at least three plants.
When not in flower, Jacob's Ladder, polemonium caeruleum forms a low, bushy mound of ferny leaves. Flowers appear on upright stems in early summer and the blooms continue for many weeks. To rejuvenate this perennial and keep the flowers coming, clip it back by half in mid-summer.
The good news about this perennial family is that they are considered easy to grow and are perfect for a woodland setting.
The bad news for gardeners like me is that Jacob's Ladder prefers somewhat moist soil. Particularly, if you live in one of the warmer climate zones, you will need to find a spot for these plants that isn't too dry, gets morning sun and afternoon shade.
It is the foliage that doggedly determines me to keep trying with this perennial. The delicate ferny leaves make it worth all the repeated attempts.
This is Jacob's Ladder, Polemonium caeruleum 'Blue Pearl' above. Height: 50-60 cm Spread: 45-50 cm. There is also a similar all-green, white flowering cultivar Polemonium caeruleum 'White Pearl'. Height: 50-60 cm Spread: 45-50 cm
Isn't this pretty?
This is Jacob's Ladder, Polemonium caeruleum 'Stairway to Heaven'. It has pale blue flowers. Height: 40-50 cm, Spread: 30-45 cm.
I think I may have to go back to the nursery and pick up a few pots of this cultivar. I love the blackish-purple leaves and maroon stems (Note: the foliage becomes greener as the plant grows).
This is Polemonium caeruleum 'Purple Rain'. The flowers are a pale mauve. Height: 40-50 cm, Spread: 30-45 cm.
This variegated form is nice too: Polemonium caeruleum 'Snow & Sapphires'. Sky blue flowers. Height 60-75 cm Spread: 40-50 cm
There are also other cultivars available besides the ones I have shown you here today.
Many off them readily self-seed, although the dogs have seen to it that I have yet to experience this family trait! To control its spread, simply trim back the flower stems after the plants have finished blooming.