Allegheny spurge, scientifically known as Pachysandra procumbens, is an easy-growing plant. Blue-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 to fill available space.
This shade-loving semi-evergreen is a native plant in 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 spurge has to offer for our southern friends!
|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, organic-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 a 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.
Its foliage is a lush blue-green hue, matte rather than shiny. 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 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 a prettier form of ground cover, too!
While it 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 southeast.
It does flower, but the flowers are not particularly showy. They develop in 2-4″ spikes which range from greenish-white to pale pink in color. This bloom happens in early spring before new leaf growth appears.
Allegheny Spurge Care
Let’s talk about everything you need to get a dense carpet of pachysandra procumbens. It’s actually fairly easy to care for, but providing the right environment starts it off right.
Light & Temperature
As the foliage of your spurge can easily sun-bleach, it’s best if grown in dappled shade. This plant thrives in the shade of large trees, as sunlight filters through the canopy.
Temperature-wise, your pachysandra 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 moisture is good for this plant. 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 plants are less than 2 years old, provide slightly more frequent watering in those initial years. This ensures they have the moisture they need to develop good foliage and expand.
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 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.
Organic-rich, well-draining soil is necessary for your plant to thrive. 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. 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 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 at the beginning of summer. Usually it isn’t necessary to apply more fertilizer, as the plant is not a heavy feeder.
Propagation from softwood cuttings is the most common method for spurges. They will readily form roots and create new plants.
Taking cuttings from your plant is best in the early spring or late fall. Select newer growth, 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 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.
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 ground cover, 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.
Little troubles this spurge species. Let’s go over what few problems may arise while you’re growing your pachysandra!
Yellowing leaves can be a symptom of one of two major problems.
Soil which is too alkaline can cause this issue. Pachysandra 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. 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.
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 stems. It also creates tan to brown spots on leaves which gradually increase in size. Over time, the 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 your soil is well-draining 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? 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 slow growing. It can and does spread over time, but it’s easy to manage and not considered invasive.
Southern US dwellers already know the charm of the Allegheny spurge. Are you ready to consider this simple ground cover plant yet? It’s worth the time to get established, as it’ll last for years and is very low-maintenance!