Pachysandra Procumbens: Allegheny Spurge Ground Cover
Pachysandra procumbens, also called Allegheny spurge, is an easy-growing ground cover plant. Our growing guide helps you get it started!
Allegheny spurge, scientifically known as Pachysandra procumbens, is an easy-growing woodland plant. Crisp green foliage provides a beautiful shrubby ground cover for all terrains. A bit slow to get started, it becomes a vibrant carpet over time and spreads slowly to fill available space.
This shade-loving semi-evergreen is one of many native plants of the United States. Its origins are in the southeast part of the country, and it’s found in abundance there. But the popularity of this spurge has spread to other regions.
So let’s see what the Allegheny spurge has to offer for our southern friends!
Quick Care Guide
|Scientific Name||Pachysandra procumbens|
|Common Name(s)||Allegheny spurge, mountain spurge, Allegheny pachysandra|
|Height & Spread||6″ average height, can spread up to 1.5 feet via rhizomes|
|Sun||Partial sun to full shade|
|Soil||Well-draining, organically-rich soil. Should be mildly acidic.|
|Water||Maintain moist, but not soggy soil. Drought resistant over time.|
|Pests & Diseases||Aphids & slugs, possibly scale & mites. May develop blight or rot.|
All About Pachysandra Procumbens
As an excellent ground cover or border plant, the Alleghany spurge is perfect. Growing not much taller than about 6″ in height, it creeps outward via underground rhizomes.
Allegheny spurge has matte blue green leaves rather than shiny ones. It may be dappled with hints of purple or white. The leaves have toothed edges at their tips, but they smooth out towards the leaf base. They may reach up to 3″ in length.
The spreading erect stems tend to be 4-6″ in length, sometimes slightly longer. They are surprisingly easy to root as cuttings, but do not develop roots on their own.
Unlike other species of pachysandra, it is non-invasive. It’s often stated that procumbens is among plants that form a dense carpet ground cover, too! It’s one of the US native plants, spreading as a woodland plant with a rhizomatous ground cover habit through the forest floors of West Virginia, Kentucky, Florida, and Louisiana.
While Pachysandra procumbens can grow easily in zones 5-9, the cooler climates have a different effect on this plant. It is deciduous in zones 5-6, but evergreen in zones 7-9. This is, in part, why it’s so popular in the woodland gardens of the southeast.
Pachysandra procumbens does flower, but when the white flowers bloom, they are not particularly showy. They develop in 2-4″ fragrant white flower spikes which are sometimes greenish or pinkish. This bloom happens in early spring before new leaf growth appears.
Allegheny Spurge Care
Let’s talk about everything you need to get your Pachysandra procumbens to form a dense carpet of matte blue green leaves. It’s actually fairly easy to care for, but providing the right environment starts it off right.
Light & Temperature
As the foliage of your Allegheny spurge can easily sun-bleach, it’s best if grown in dappled shade or full shade. This plant thrives in the shade of large trees, as sunlight filters through the canopy.
Temperature-wise, your Pachysandra procumbens prefers moderate climates. It grows well outdoors in zones 5 to 9. Even in moderate climates, it can begin to look a bit ragged in winter, but it recovers once warm weather returns.
Water & Humidity
Consistent medium moisture is good for Allegheny spurge It doesn’t require heavy watering, but it likes the soil to be moist at all times. An inch a week is likely all you’ll need to keep it happy.
If your Pachysandra procumbens plants are less than 2 years old, provide slightly more frequent watering in those initial years. This ensures they have the medium moisture they need to develop good foliage and form a dense carpet of matte blue green leaves.
Avoid overhead watering for Pachysandra procumbens. It is susceptible to leaf blight problems, and these can make them worse. When possible, use a soaker hose at the base of the plant for slow, gradual watering purposes.
Tolerant of southeastern US humidity, your Pachysandra procumbens plant can hold on in both dry and wet air conditions. It will accept dryer air, of course, but seems to thrive at about 50% humidity.
Your Allegheny spurge likes mildly acidic soil. Aim for a range which is 5.5-6.5 pH. If you’re not sure about your soil’s pH level, do a pH test before you plant. This gives you the ability to amend the soil before planting.
Organically-rich, well-draining soil is necessary for your Pachysandra procumbens plant to thrive and form a dense carpet. It should remain consistently moist for best development. Adding peat moss to your soil can help with moisture retention. Leaf mold is another great option, as is forest humus. Ensure excess water drains away easily.
Fertilizing in the early spring is best for your Pachysandra procumbens. Most spurge species prefer a balanced fertilizer in the 10-10-10 or 12-12-12 range. Slow-release granular options are easiest to apply around your shrubby ground cover plants. Follow the manufacturer’s instructions for application.
Apply your fertilizer just as new growth begins to form. If necessary, you can apply a second dose in early summer. Usually it isn’t necessary to apply more fertilizer, as the plant is not a heavy feeder and its white flowers bloom either way. It will form a dense carpet through its rhizomatous ground cover habit regardless.
Allegheny Spurge Propagation
Propagation from softwood cuttings is the most common method for spurges. They will readily form roots and create new plants via their rhizomatous ground cover habit.
Taking softwood cuttings from your Pachysandra procumbens plant is best in the early spring or late fall. Select newer growth before white flowers bloom, and cut off a piece which is at least 4″ long. Dip the end into rooting hormone and place into moistened potting soil. Keep the soil moist while roots form.
You can also divide the rhizome of your Pachysandra procumbens plant. Select a larger plant and cleanly cut through the center to divide it in half. A sterile, sharpened shovel blade works well for this purpose. You can then transplant one half while the other remains in place.
Pruning Allegheny Spurge
As Pachysandra procumbens tends to stay around 6″ in height, you may not need to prune for height at all. If you’re using it as a dense carpet ground cover, this requires medium maintenance. You can set your lawnmower at 4″ and trim it down to a consistent size if you wish.
Slow-growing, this spurge doesn’t tend to be invasive like its relative Pachysandra terminalis. That one, the Japanese spurge, will rapidly invade other spaces. With your Alleghany spurge, you should find that a light edge trimming keeps it in check.
Troubleshooting Allegheny Spurge
Little troubles this spurge species that thrives in woodland gardens. Let’s go over what few problems may arise while you’re growing your Pachysandra procumbens!
Yellowing leaves can be a symptom of one of two major problems for Pachysandra procumbens.
Soil which is too alkaline can cause this issue. Pachysandra procumbens plants prefer a slightly-acidic soil, and if the pH is too high, they won’t thrive. They can develop pale green or yellowish-looking leaves or be stunted in growth. Raising the acidity of the soil can help with this.
The other problem comes from too much sunlight. Full sun conditions can cause the leaves of your plant to bleach. Yellow-green leaves are common in this situation. They may appear burned or become brittle. Ensure your plants are in partial to full shade.
Multicolor leaves are not uncommon on a dense carpet of Allegheny spurge. As seasons change, you may notice your pachysandra developing silvery or whitish leaf patterns. This is not harmful to your plant and, in fact, is sometimes referred to as the plant “opening its windows to let in the light”. It’s particularly common in autumn when the days are growing shorter.
Pests of Allegheny Spurge
Most pests tend to ignore Allegheny pachysandra. Those which do are opportunistic and are usually found on multiple plants at the same time.
Aphids are among these opportunistic pests. Treatment of these can be as simple as using a hard spray of water to rinse them off. Applying neem oil can keep these at bay.
Slugs are also quite common, as the spurge provides both shelter from the sun and food. Using an organic snail and slug bait provides the best protection for your plants.
Other pests which are less-common include spider mites and scale. Both are fairly rare on your spurge. Neem oil is a common preventative for these as well.
Volutella stem and leaf blight strikes multiple types of pachysandra. While pachysandra procumbens is more tolerant of it than other forms, it can still strike. This fungal blight causes cankers on erect stems. It also creates tan to brown spots on leaves which gradually increase in size. Over time, the leaf blight can completely cover the leaf surface.
Promoting good air circulation around your spurge plants helps reduce volutella blight. It is more common in damp or rainy conditions, so avoid overhead watering. As the weather warms up, it’s less prone to develop. Apply copper fungicide to prevent further spread, and trim off damaged material.
A variety of root or stem rots can also form in overly-moist conditions. These mainly develop in poorly-drained soil. Fungal causes include pythium, fusarium, or alternaria among others. For these, prevention is better than trying to cure. Ensure you have well-drained soils and that roots won’t be in standing water conditions.
Frequently Asked Questions
Q: Can I grow pachysandra procumbens as a lawn replacement?
A: You can if you’ve got a partially to fully shaded lawn area. While short periods of full sun may not do severe damage, longer periods will. This plant is excellent as a groundcover under the shade of trees or in shaded areas alongside buildings.
Q: Is fertilizing absolutely necessary for Allegheny spurge?
A: Is it required? No. Does it help the plant to develop and spread in well-drained soils? Yes. If you’re trying to avoid commercial fertilizers, you can apply about an inch of compost in the spring around your plant. That should give it the nutrition required for growth. Regular fertilizers are just easier to apply.
Q: Is pachysandra procumbens invasive?
A: The short answer is not really. While other forms of pachysandra are, particularly pachysandra terminalis, procumbens is a member of groups of slow growing native plants. It can and does spread over time, but it’s easy to manage and not considered invasive.
Q: Does pachysandra like sun or shade?
A: It’s a partial to full shade plant.
Q: Will pachysandra spread on its own?
A: It will! It’s among other US native plants that thrives and spreads slowly in shady areas.
Q: What is the best time of year to plant pachysandra?
A: Plant it in temperate fall or spring, and do so when the plant has enough time to establish itself before the cold of winter or heat of early summer sets in.
Q: What happens to pachysandra in the winter?
A: Unless you live in an area with arctic winters, it should remain green. You may see some die back in cooler zones, but overall the plant will survive.
Q: Will pachysandra take over grass?
A: Yes. It is known to take over nearby vegetation and garden beds.