There are two species of Jacob’s ladder plant that are commonly found in the garden. The first, Polemonium reptans, is native to the northeastern quadrant of the United States and is considered a threatened species in some states. Environmental care of Jacob’s ladder includes discouraging gardeners from taking plants from the wild for transplant. Instead, try growing Jacob’s ladder Polemonium caeruleum, the species developed for the garden, which is rarely found growing in the wild.
I. Appearance and Characteristics
Polemonium reptans is a perennial herbaceous plant native to eastern North America. Common names include spreading Jacob’s ladder, creeping Jacob’s ladder, false Jacob’s ladder, abscess root, American Greek valerian, blue bells, stairway to heaven, and sweatroot.
Polemonium reptans is typically found in rich, moist woods, often along streambanks. Its range extends from Minnesota to New Hampshire in the north, and from Georgia to Mississippi in the south. It is most abundant west of the Appalachian Mountains.
Jacob’s ladder grows 50 centimetres (20 in) tall, with pinnate leaves up to 20 centimetres (8 in) long with 5–13 leaflets. The leaves and flower stems grow from a vertical crown with abundant fibrous roots.
The flowers are produced in panicles on weak stems from mid to late spring. They are 1.3 cm (1⁄2 in) long and have five light blue-violet petals that are fused at the base, enclosed by a tubular calyx with five pointed lobes. The pollen is white. The stigma extends beyond the anthers, making self-pollination difficult, so insects must cross-pollinate for the plants to produce seed.
Pollinated flowers develop into an oval pod with three chambers, 6 mm (1⁄2 in) long, which is enclosed by the green calyx. The plant spreads by reseeding itself. The Latin specific epithet reptans means creeping.
The flowers produce both pollen and nectar. Long- and short-tongued bees visit the plants for both nectar and pollen, syrphid flies and fire beetles (Pedilus lugubris) feed on pollen, and butterflies and moths drink nectar. Out of these insects, large bees are the most effective at cross-pollination, since they most often touch the pollen-covered anthers.
The plant prefers partial shade and mesic soil. It tolerates full sun, but requires constantly moist soil.
II. How to Grow and Care
Sunlight and Soil
The Jacob’s ladder plant is a woodland perennial that prefers a shady to semi-shady spot for growing. Jacob’s ladder leaves tend to scorch with too much heat or sun. It grows best in soils that are rich in organic materials and likes a moist, but not soggy environment. That being said, one of the pleasures of this garden addition is that it tolerates drought once its root system is firmly entrenched.
Water and Humidity
This plant prefers uniformly moist soil conditions, but it does not tolerate stagnant water. It is important that you choose a well-drained soil to ensure that it does not piss around the plant.
In general, the frequency of watering should be measured by the development of the plant. As a shade-tolerant species, there is a little less evaporation than if it was directly exposed to the sun all day, which means that your watering frequency varies depending on the lighting it receives.
Fertilizing
If you apply a layer of compost around your plant several times a year, you probably don’t need fertilizer at all!
However, if you choose to use a separate fertilizer, aim for an early spring feeding with a balanced fertilizer. This promotes new growth. Feed again as soon as the flowers have wilted and the flower stems are cut to try to encourage new flowering.
Pruning
Deadheading can be done to encourage continuous bloom. Cut the flower stalks back to the base of the plant. After flowering, cut the plant back by one-third to stimulate re-bloom.
Propagation
Once you’ve located a spot suitable to their needs, there are two methods of propagation: by seed or by plant division.
- Seeds
Cultivars won’t always breed true from seed, but if you’re not concerned with specific colors, seeds (either purchased or self-sown) can yield some interesting results. Sow the tiny brown seeds directly into the soil in spring after all danger of frost has passed. Loosely cover the seeds with a fine sprinkling of soil, water gently, and keep moist until seedlings sprout. The seeds will germinate quickly and should be thinned to about 18 inches (46 cm.) apart. You’ll get a fine showing of foliage the first year but may not see flowers until the second season.
- Divisions
For the best results and care of Jacob’s ladder, divisions should be made in the early spring just as new growth appears. Carefully dig the entire plant from the ground. Separate the basal rosettes by tearing apart the roots and replant each of the resulting Jacob’s ladder plants in its new spot. This is also a great time to replenish that area of the garden with rich, organic soil. Water your transplants well and keep the ground moist for a few weeks to give the plant’s roots time to settle into their new home.
Transplanting
The perfect time to transplant Jacob’s ladder is during the cooler months, from early summer through late fall. Choose a partially shaded location with well-drained soil for transplant success. Gently loosen the root ball for optimal growth.
Pests and Diseases
There are a very limited number of pests that seem to strike this plant. In fact, it is resistant to deer and tends to be generally resistant to pests! But there are a few things that can make it acceptable.
Minors can come to visit. These tiny pests chew lines through the leaves of your plant, and although the leaves are smaller than other types of foliage, this does not prevent them from making a quick meal on your plant.
With this, it can be difficult to wipe them off. However, you can choose to initially repel them by regularly spraying neem oil on all leaf surfaces to keep the pests away. The introduction of beneficial nematodes into your soil can help finish the mature pupa.
Some fungal leaf spot conditions may persist in wetter conditions. Although these usually don’t finish your plant, they can make it difficult for the plant to produce chlorophyll, which can slow down growth. Use Monterey Liqui-Cop or another copper fungicide on these.
In general, the most common ailment of the Jacob’s scale is powdery mildew. This is also caused by moisture or the accumulation of moisture on the leaves and causing the right conditions for the growth of fungi. Neem oil is an excellent way to treat this ailment and prevent its further development.
Maintenance
These plants require minimal maintenance. After blooming, they can become leggy and need trimming. Jacob’s ladder plants will rebloom if the flower stems are cut back to the base. Sometimes, especially in older plants, the foliage can become brown and tattered looking. Trim out all unsightly foliage and new growth will begin almost immediately. Trimming Jacob’s ladder plants and the occasional foliar feeding is all that’s needed for the yearly care of Jacob’s ladder in the garden.
III. Uses and Benefits
- Ornamental uses
Jacob’s ladder is a far-flung decorative plant found in rock gardens and wildflower gardens. It spreads quickly and makes a good ground cover or border plant, while its bright blue blossoms make it a wonderful showy plant in shady garden beds. The blooms last through spring and summer, and hungry deer will generally leave it alone.
- Medicinal uses
The dried roots have a slightly bitter and acrid taste. P. reptans has been traditionally used as an herbal medicine for febrile and inflammatory diseases, to ease coughs, colds and bronchial complaints, and to encourage perspiration. It is furthermore said to bring relief in cases of inflammations and infections. The root is rarely used in modern herbalism. It is harvested in the autumn and dried for later use.
