Epic Gardening is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Learn more
Flowers, Foliage

Jacob’s Ladder Plant Care: Growing Polemonium Caeruleum


13 min read

Once upon a time, Jacob’s ladder plant was called the “charity plant,” although it shouldn’t be confused with the Mahonia species that also bears that common name. It’s also been called “Greek valerian,” although it’s not a valerian. Confused yet?

You shouldn’t be. Jacob’s ladder gets its common name from the ladder-like or pinnate structure of its leafy foliage. And in the spring and early summer months, it shoots up slender stalks from which hang clusters of bell-like flowers.

A shade-loving variety, it has origins overseas but is often found in the United States in garden cultivation now. It’s such an easy-growing plant that it can even be considered slightly invasive if it’s in the right environment! However, it can be maintained and kept to its beds as well.

Let’s delve deep into the world of the Polemonium species, and I’ll tell you all about this beautiful perennial!

Subscribe to the Epic Gardening Podcast on iTunes or Spotify

Good Products At Amazon For Growing Jacob’s Ladder Plants:

Overview

Jacob's ladder plant
Jacob’s ladder plant. Source: Rachel James
Common NameJacob’s ladder, charity plant, Greek valerian
Scientific NamePolemonium caeruleum
FamilyPolemoniaceae
LightPartial to full shade
WaterEvenly moist watering required, more in summer months, no standing water
HumidityTolerates humidity but can develop fungal diseases in higher humidity environments
SoilRich, well-draining soil with lots of composted plant matter
FertilizerRegular applications of compost is best. If using fertilizer, apply balanced fertilizer once in early spring and again after blooms fade.
PestsLeaf miners and slugs. Also eaten by groundhogs and chewed/rolled on by cats.
DiseasesPowdery mildew, fungal leaf spot

All About Jacob’s Ladder Plant

Polemonium reptans, or "false Jacob's ladder"
Polemonium reptans is a related species sometimes called false Jacob’s ladder. Source: woolcarderbee

With its origins in the temperate regions of Europe and Asia, Jacob’s ladder plant – aka, Greek valerian – is a beautiful addition to any garden. That’s largely why it’s become naturalized in multiple environments worldwide today, including eastern North America!

Jacob’s ladder is native to areas of meadowland, woodlands, and grasslands, this shade-loving species derives its name from its pinnate leaves that resemble the rungs of a ladder. It is an excellent low-maintenance plant that is often grown as a deer-resistant flower in many gardens.

There are two species that carry the same common name. The one we’re focusing on today, Polemonium caeruleum, is the cultivated variety that can be found at your local garden center. Optimized for garden growing, it’s a highly-desirable burst of color in shadier locations.

A related species, Polemonium reptans, is referred to as “false Jacob’s ladder” or “creeping Jacob’s ladder.” Native to the northeastern United States, it is considered a threatened wild plant in some states. It’s not ideal in a garden environment due to its tendency to be very leggy.

Growing about 18-24 inches in height, Polemonium caeruleum often reaches a similar width to its height. Some cultivars can become even larger, up to about three feet tall. Most have dark green leaves.

The leaves of Greek valerian may be fully, vibrantly green and lush or may have other colorations. Examples of the variegated varieties are “Stairway To Heaven,” which has cream-colored foliage, or “Bressingham Purple,” which has deep green foliage streaked with dark purple.

Jacob’s ladder blooms in the spring to early summer months, often at the same time as allium species and the bleeding heart plant. Bell-shaped flowers hang in clusters from the end of their flower stalks and may range in color from blue to pink, yellow, purple or white.

For most of its preferred growing environments, Greek valerian can easily be grown as a perennial. In some locations, it acts as a self-seeding annual. In eastern North America, this plant is perennial.

Jacob’s Ladder Plant Care

Purple Jacob's ladder plant flowers in bloom
Purple flowers in bloom. Source: Peter Stevens

Easy to grow, it’s suited to beginning gardeners in a wide range of locations throughout the United States and Europe. As far as flowering plants go, this is a great starting choice!

Light & Temperature

While I wouldn’t consider it to be a low-light plant, Jacob’s ladder prefers less light. It wants to grow in shady or semi-shaded spots, mostly because it can develop sunburn if it’s in too much direct sunlight.

Now, there are cultivars that are much more tolerant of direct sunlight than others. Green and leafy varieties are often more tolerant than the variegated-leaf varieties.

It can be difficult to strike the right lighting balance to promote flowering without causing damage to the plant’s leaves. If this is your situation, it’s best to opt for a healthy, foliage-dominant plant than to try to push for heavy flowering. It will flower, just a bit less.

Greek valerian is considered a shade perennial, but some varieties do act as annuals in cooler climates (hardiness zones below 6). Overall, the plant flourishes in zones 3-8 but can be grown in many more, even up to zones 10-11. It just needs to be in a more protected location if it’s hot.

Water & Humidity

The Greek valerian plant prefers to have evenly-moist soil conditions, but it won’t tolerate standing water. It’s important that you opt for well-draining soil to ensure that it doesn’t puddle around the plant.

Overall, the frequency of water should be gauged on how well the plant is developing. As a shade-tolerant species, there’s a bit less evaporation than if it were directly in the sunlight all day, which means your watering frequency varies depending on what lighting it gets.

Aim for consistency. Your plant is somewhat adaptable and in fact, can be quite drought-resistant once its roots are firmly established. It may require extra watering during the hotter months of the year, but otherwise, consistency is key.

Humidity can become a concern for Jacob’s ladder (Polemonium), as it’s prone to powdery mildew. Avoid wetting the leaves directly whenever possible, and provide good airflow around your plant.

Soil

In regards to the soil, Greek valerian loves soil that’s rich in organic material. Heavy applications of compost are recommended to make your plant thrive at its peak!

Prior to planting, blend in a good amount of compost to your planting bed to encourage ready growth. Make sure that the soil is still well-draining so that standing water doesn’t build up, as this can cause root rot to develop. Avoid or amend poor or clay-like soils.

While pH doesn’t appear to be a common issue for Greek valerian, aiming for a neutral range is usually best for whatever other plants you decide to pair with it.

Fertilizer

If you apply a layer of compost around your plant a couple of times per year, it probably won’t need fertilizer at all!

However, if you do opt to use a separate fertilizer, aim for an early spring feeding with a balanced fertilizer. This promotes new growth. Feed again once the flowers have faded and the flower stalks are cut back to try to encourage another flush of flowering.

Propagation

You can propagate with Jacob’s ladder seed, or do it by division. Cuttings may also work, but fail more often than they succeed.

Greek valerian seeds should be sown directly into the soil after the risk of frost has passed in the spring. Cover them with a light dusting of soil and keep them moist until seedlings appear. Thin to 18″ apart. Your plants produce lots of foliage in their first year and may not flower until subsequent years.

If you wish, you can allow your plant to go to seed, as it will readily self-seed its area. It comes back in a much denser distribution over time, and you may want to divide the plants later.

To divide your plants, carefully dig the plant out of the ground being especially careful not to damage its roots. Gently separate the rosette-like bases of the plant, teasing apart the root system. If necessary, you can cut especially entangled roots.

Replant your plants in freshly-prepared soil and water them in thoroughly. Even if you don’t opt to divide your plants for propagation purposes and don’t allow them to self-seed, division should happen every 3-4 years. This ensures your plant has room to grow and develop.

Repotting

Much as described in the propagation section, you will carefully remove your plant from its existing soil, being sure not to damage the root system. Replant at the same height the plant was initially planted. If there are multiple bases, you might want to divide them up at this time.

Pruning

You won’t need to prune for any serious reason. Pruning Jacob’s ladder is mostly aesthetic in nature!

If your plant is starting to get a bit leggy, you may wish to trim back excessive growth to keep it more evened up and visually appealing.

When deadheading spent flowers, cut the stalks to the base of the plant. Simply wait for the flowers to fade first. This encourages them to rebloom if the weather conditions are good for producing flowers.

Older plants may develop browned or beat-up, ragged-looking foliage towards the end of the summer months. You can prune out all of the damaged material, allowing the plant to fill back in with new growth.

Troubleshooting

Lavender to white flowered plants
Lavender to white-flowered plants. Source: Peter Stevens

Most pests don’t seem to care for it, but there are a few. Diseases also aren’t super-common but can happen. Here are some tips to help you if any problems arise!

Growing Problems

As mentioned before, too much direct sunlight can cause foliage to get sunburned.  It’s not a bad idea to test the future location of your plant by placing a potted one in the location where you’re considering a permanent placement and seeing how it does there. If it’s good, plant away!

Too little water can cause the tips of the leaves to turn brown and crispy. While it’s surprisingly drought-tolerant once established, younger plants often experience this problem when underwatered. Stay consistent in your soil moisture.

As the heat of the summer reaches its peak, you may find that the foliage of your plant becomes less attractive. This is especially true if you’re growing in a hotter climate than zone 8. By the end of the summer, it may be leggy and browned in patches, requiring light pruning.

Pests

There are a very limited number of pests that seem to attack this plant. In fact, it’s deer-resistant and tends to be pest-resistant overall! But there are a few things which may find it to be tasty.

Leaf miners may come to visit. These little pests will chew lines through the leaves of your plant, and while the leaves are smaller than other types of foliage, it doesn’t stop them from making a quick meal on your plant.

With these, it can be difficult to wipe them out. However, you can opt to repel them initially by regularly spraying all leaf surfaces with neem oil to keep the pests at bay. Introducing beneficial nematodes to your soil can help with killing off pupating adults.

Slugs are notorious for snacking on Jacob’s ladder, and they too can be difficult to stop. Use bait to lure these pests away from your plants and poison them.

Finally, there are two animals that are enticed closer by this plant. Cats are especially attracted to younger plants, as they smell similar to catmint. In addition, groundhogs find the foliage absolutely delectable.

These two pests can be harder to repel than normal pests as they’re persistent. However, putting a wire cloche over your plant should deter them, as can a floating row cover. As your flowers also draw pollinators, a floating row cover is a temporary solution at best.

Diseases

Blue Jacobs ladder flowers
Blue Jacobs ladder flowers. Source: Andrew Hall

Much like insects, very few diseases are likely to strike your plants. However, there are two which are fairly common.

Some fungal leaf spot conditions may persist in more humid conditions. While leaf spot diseases are generally not likely to kill your plant, they can make it hard for the plant to produce chlorophyll, which can slow its growth. Use Monterey Liqui-Cop or another copper fungicide on these.

By and large, the most common disease for Jacob’s ladder is powdery mildew. This is also caused by moisture or humidity building up on the leaves and causing the right conditions for fungal growth. Neem oil is a great way to treat this condition on the plant’s dark green leaves and prevent further development.

In both fungal leaf spot or powdery mildew situations, you may be able to carefully remove the affected foliage and throw it out, preventing spread. But if it’s advanced beyond just a few early spots, it’s best to treat the problem rather than remove it.

Frequently Asked Questions

Q: Where is the best place to plant Jacob’s ladder?

A: Plant them in an area where you can keep the soil moist but well-draining and in a spot where there is some shade.

Q: Is Jacob’s ladder plant invasive?

A: Also known as Greek valerian, is not considered invasive in any region.

Q: Is Jacobs ladder a shade plant?

A: Yes, it enjoys more shade than many plants.

Q: Does Jacob’s ladder bloom all summer?

A: The blue flower of this lovely plant tends to die back as the heat of summer sets in.

Q: Should Jacob’s Ladder be cut back?

A: As the flowers finish blooming, feel free to deadhead spent flowers as they crop up. Or cut them back if they’re getting leggy.

Q: How deep do you plant Jacob’s Ladder?

A: Press seeds of Greek valerian plants into the ground and lightly cover them with no more than 1/8 inch of soil.

Q: Is Jacob’s Ladder poisonous?

A: Yes. Do not consume it, and keep it away from pets and children.

Q: How do you winterize a Jacob’s Ladder?

A: Cut them back to the ground in summer, and cover them with a layer of mulch. This will keep the soil moist and protect the roots in winter.

Related Categories
Products in this article