Growing Northern Jacob's Ladder

Let's start with P. caeruleum, it's sometimes known as Greek Valerian. It grows from a foot to 3 foot tall, and does well in cool, moist, partial shade. It can tolerate full sun in cooler climates. This form of Jacob's Ladder is hardy in most of Zone 5 through 10 and may be planted from seed. It will bloom the second year, but the foliage is pretty, so that will benefit your landscape. The flowers are a sky blue. It may go dormant in very high humidity, so a shady, woodland type location is really important in the hot zones. The foliage is ferny, so it goes well with other woodland plants.

P. reptans, only grows to 6-8 inches and blooms earlier in April. This variety can become weedy in some areas if left to it's own. But it pulls up fairly easily, and it's such a pretty plant that a few volunteers would be welcome. This Jacob's Ladder is considered a woodland wildflower. The small bell-shaped flowers are blue and it grows along streams, in moist or even rocky woods. It has been used as a medicinal plant in the past and is hardy in Zones 3 to 9. One interesting feature is P. reptans ability to grow beneath black walnut trees. The tree's roots produce, juglone, which is a toxic substance that causes many plants to die if they are grown within 50 or so feet of the root zone--sometimes up to 80 foot in an older tree. (Note: Don't put your vegetable garden near a black walnut!). Deadhead P. reptans after it blooms. It's spread will be about 8 inches or so. It's a nice Jacob's Ladder for locations where you want a shorter, spreading plant.

P. boreale is a pretty Jacob's ladder that grows to about 12 inches tall with violet blue flowers that have a bright yellow "eye". The flowers are larger and more fragrant than the other varieties. It's foliage also has a glossier appearance. P. boreale likes a cool, moist soil with protection from the hot sun. Deadheading may also provide you a second bloom in late summer, so cut them back after bloom! It's hardy in Zone 3 and has a "clumping" type habit. It can be grown from seeds, which germinate at about 68 degrees F. Sow the seed and cover VERY thinly, keeping the soil moist, but not soaked.

Jacob's Ladder varieties don't do well in clay or standing water, but the soil should be very fertile with organic matter added. Remember if you do start it from seeds germination can be erratic--up to 30 days, but it may be less. Start inside or direct seed in a prepared area. All of the Jacob's Ladder plants have attractive foliage, and the blooms are a cheerful addition to the foliage.