Heuchera [HEW-ker-a] is a lovely North American native shade perennial named after the German physician, Johan Heinrich von Heucher early in the seventeenth century.
Heuchera is commonly called Coral Bells, a reference to the plant’s pretty, bell-shaped flowers.
It’s also called Alum Root because the root has a variety of uses in folk medicine.
It has an astringent taste reminiscent of alum.
There are several different species in the Heuchera genus, all of which are North American natives.
Heuchera is a member of the Saxifragaceae family which also includes a number of other interesting shade plants.
Size & Growth
Alum Root attains a height of 1’ – 2’ feet and a maximum spread of 1½’ feet.
The original Heuchera had green leaves, but hybridization has resulted in a wide variety of interesting shades including red, pink, purple, orange and yellow.
Some Heucheras have nearly black leaves.
In some species, leaves may provide a tremendous show of autumn color but leaf sizes vary.
Flowering & Fragrance
Flowers are small bell-shaped and come in shades of red, pink, white and greenish-white with hints of red.
The plant blooms freely throughout the summer months.
Light & Temperature
These plants prefer to get their sunlight in the morning hours rather than in the hot afternoon.
All species of Heuchera do quite well in a soft shade.
There are some darker leaved varieties performing in a wider range of lighting, from full sun to complete shade.
Species with white toned or pale green leaves like to be kept in shady locations because the pale-colored leaves burn easily.
Plants with deep red or purple tones do well in sunnier settings.
Read the description of your plant carefully when purchasing it in the nursery to ensure you place it in the right location.
Alum Root is winter hardy in USDA hardiness zones 4-9.
Watering & Feeding
When planted correctly with the right quality of soil and in the right location, Heuchera won’t need frequent watering.
Established plants are quite drought resistant. Excessive watering will lead to root and crown rot.
Too little watering will naturally lead to wilted or dead plants. Check the soil frequently and water as needed.
As with most native plants, infrequent deep watering is preferable to frequent light watering.
Water at soil level, and avoid getting water on the leaves.
Water your plants thoroughly when you plant it, and add some mulch to prevent weed growth and to help the soil retain moisture.
If you add plenty of organic matter to the soil, your Coral Bells will likely not need fertilizer.
If you do decide to fertilize, use a half-strength application of general-purpose garden fertilizer.
Slow-release fertilizers also work well.
If you over-fertilize, you will get lots of leaves but few or no flowers.
Furthermore, excessive fertilizing causes your plant to need more water.
It’s best to fertilize lightly, or not at all and simply allow your plant to rely on organic soil amendments in the form of organic matter for nourishment.
Soil & Transplanting
Coral Bells does well in crumbly, soft, humus-rich and very well-draining soil.
The reason for this is these plants grow naturally on slopes or cliffs where water is not able to stand.
The plant family name, Saxifragaceae, means “rock breaker.”
If your garden soil is heavy, amend it with organic material such as chopped leaves, rotted manure, or compost.
Incorporating organic matter into the soil will help provide air pockets so the plants’ roots get enough oxygen.
Furthermore, organic matter provides a steady, slow supply of food for the plant as it decomposes.
Heuchera prefers a slightly acidic soil (5.82 – 6.3 pH); however, it will tolerate a wide range of pH levels.
When you plant your Heuchera, dig a hole twice as deep and wide as the plant’s root ball.
Put some loosened soil in the bottom of the hole so the plant’s root system can expand easily.
Take your plant out of its pot and massage the roots to loosen up any compacted soil and stimulate the root ball to grow.
Position the plant so its crown is just a little bit higher than the soil line.
Be very careful not to bury the plants crown as doing so will lead to fungal diseases and crown rot.
Good air circulation is essential for Coral Bells to thrive.
Grooming & Maintenance
In the far northern United States, you should mulch your Heuchera during the wintertime to prevent freezing.
Just toss a layer of straw or leaves over your plants during the winter months and remove them in the springtime.
You may also wish to prune your plant in springtime to keep it tidy looking.
Deadhead the flowers as they fade to encourage more blooms.
Look out for frost heaving.
This is a situation in which the crown of the plant is slowly pushed out of the ground as the ground expands from freezing.
If you see your plant seems to have been shoved up above the soil surface, simply sprinkle fresh soil over it to cover the crown lightly.
Alternately, lift the plant and divide it if it has been in place for several years.
If you’re replanting your Heuchera in the same hole, dig it in a little bit deeper.
In mild climates, Alum Root stays green year-round and adds lots of interest to your winter garden.
Growing year-round can cause your plant to look a bit ragged in the springtime, groom well as the weather warms.
How To Propagate Coral Bells
Propagate Coral Bells easily through division. When you see the center of the plant is becoming woody and growth slows down, it’s time for division.
This happens once every three or four years. In some species, you may notice the crown raises above the ground.
This is another indication you’ll need to divide the plant.
The division is usually the most successful in the springtime as this gives the newly divided plant plenty of time to establish itself in its new setting and put down a strong system of roots before the winter months.
Use sterilized gardening tools when digging up and dividing your Heuchera to prevent the spread of disease.
Coral Bells Pest or Diseases
These hardy native plants are very seldom bothered by diseases or garden pests.
The most likely problem is a fungal disease caused by improper planting or excessive watering.
If you remember to give your Coral Bells light, airy soil and plenty of room for air circulation, along with deep, infrequent watering you should not have any problems with fungal infections or pests.
If you’re keeping your Heuchera in a greenhouse, it may be subject to rust, which is a fungal disease.
If you see brown or orange pustules on the undersides of the leaves, your plant is suffering from rust and should be treated with a fungicide.
Both Black Vine Weevils and Strawberry Root Weevils may occasionally be bothersome for Heuchera.
Weevil larvae hatch late in the wintertime and also during the early springtime.
As they emerge, they feast on plant roots and succulent stems.
They may especially attack Coral Bell crowns.
To prevent problems with weevils, drench the plant crown with a pyrethrum spray solution in autumn.
Spraying the entire plant in the spring may also be effective.
Alternately, diatomaceous earth (DE) sprinkled on and around the plants can effectively deter these pests.
Encourage predatory nematodes in your garden to reduce your weevil larvae population.
Follow all packaging instructions when introducing predatory nematodes to ensure success.
For the most part, Alum Root is deer resistant; however, in very lean years, deer, rabbits, and other animals may resort to eating this bitter-tasting plant.
Is the plant toxic or poisonous?
According to the American Society for the Prevention of Cruelty to Animals, Heuchera is non-toxic to cats, dogs, and horses.
Is the plant invasive?
Although Coral Bells is a native plant and grows freely in North America, it is not considered invasive.
Suggested Heuchera Uses
The foliage and flowers of Coral Bells are welcome additions to floral arrangements.
When kept in a vase, Alum Root leaves can last more than a month.
The flowers will last approximately one week.
Plant Coral Bells in containers, throughout woodland areas, in your rock garden and alongside paths and borders.
The sturdy plants also make a lovely groundcover in a shaded yard.
Coral Bellflowers are very attractive to pollinators such as bees, butterflies, and hummingbirds.
Plant them in your butterfly or pollinator-friendly garden.