How to Plant, Grow, and Care For Irish Heath

I’ve never been to Ireland in person to see the expansive, flower-covered heaths of the North. But I’ve seen photos and it’s glorious. The sheer volume of this sweet plant growing across the moors and heathlands of the island is a sight to behold. Swaths of purple roll over the mostly infertile, boggy landscape, a surprising testament to the hardiness of the plant. 

Learn how to grow this lovely purple-flowered evergreen in your garden!

What Is It?

Irish heath is a type of heather. In fact, it’s often referred to as Irish heather. It’s famous for growing across the barren moors of Northern Ireland, covering the ground with a carpet of purple for a long portion of the year. The plants bloom from June through October, lighting up the summer. 

St Dabeoc’s heath is another common name you might hear in reference to this particular plant. It’s popular as a garden plant for containers or as a ground cover. In addition to its beauty, it’s an excellent food source for pollinators while in bloom.

Characteristics

Irish heath is a small, perennial, evergreen shrub. It grows to a maximum of three feet and has foliage that is somewhat needlelike. In this way, it resembles some herbs like rosemary or lavender. Low and shrubby, it branches nicely and spreads wider than it grows tall. 

From June through October, the evergreen has a long blooming season. The flowers are small and bell-shaped, appearing in umbel clusters at the ends of branches. They’re usually red, purple, pink, or white, with a pinkish purple being the most common. 

The flowers remain in place for some time after pollination, so they retain color for a significant portion of the year. It’s a valuable plant to pollinators with a rich nectar and pollen supply. 

Heathers look wonderful planted in large drifts, where they will act as a spectacular ground cover. This is what makes those Irish heaths so special. The mass of plants that grow together seems to form a dense carpet of green and purple, covering otherwise boggy soil where little else grows. 

Native Area

This evergreen is native to Ireland, from which it gets its name. It’s also found naturally in other parts of Western Europe, such as Spain, France, Portugal, and the Azores. It mainly grows in coastal areas, on cliffs, in rocky areas, and on the moors, where it appreciates the rainy, mild climate. 

Planting

You can plant Irish heath at about any time of year, but there are times that are better in terms of establishing roots. It prefers mild and moist weather, so spring and fall are best. Don’t plant in frozen ground or if you’re expecting a frost soon. Temperature extremes cause stress and slow down the establishment of roots. 

Dig holes that are as deep and twice as wide as your containers or root balls. This loosens the dirt in the immediate area, making it easier for roots to break through. Plant individual plants about one foot apart to allow them space to spread out. 

After planting, make sure to water your Irish heath generously. These are moisture-loving perennials that thrive in boggy environments. Add a thick layer of mulch to protect the roots and hold in moisture. For the first six months, make sure to keep the soil moist. Watering will depend on your climate and the time of year. 

Growing from Seed

You can grow this plant from seeds. Just be prepared to be patient. It can take up to six months for seeds to germinate. Use an acidic potting mix and sow the seeds covering them only lightly. Use a spray bottle to moisten the potting mix, and keep it moist throughout the process. Avoid allowing it to get soggy. 

It’s helpful to maintain higher humidity while they are germinating and young seedlings. You can create a small greenhouse by covering the seed trays with plastic wrap. Leave vents, and don’t wrap it too tight, or you’ll risk rotting your seedlings. Place them in a warm spot, away from direct sunlight, and maintain the moisture. 

How to Grow

Irish heath is not difficult to grow. Once it’s established, it’s relatively drought tolerant. There are few pests or diseases to contend with, and as long as the soil has proper drainage, there is little else to worry about. It is flexible in most ways, except for the pH of its soil.

Light

Ideal sun conditions will vary according to your climate, but in general, Irish heath likes full sun. At least six hours is what will give you the most robust, vibrant foliage and flowers. The exception is in hot climates, where it will benefit from some shade in the afternoon.  In zones nine and ten, I would recommend partial shade. 

Water

This is a moisture-loving plant, and it won’t be happy in dry soil. It does need good drainage, as a result, so that it doesn’t develop root rot. Potted Irish heath will need more water than those in the ground. The amount of rainfall you receive is another influencing factor. Essentially, don’t let it dry completely between waterings, but don’t water so often that it stays soggy. 

Soil

One area of care that is non-negotiable is soil pH. Irish heath needs an acidic environment—a pH of four to six is ideal. It also needs to drain well. Dense, compacted soil can be an issue when it comes to drainage. Poor drainage leads to the only significant issue these heaths face: root rot. A combination of loam and sand with some peat is a good composition for the soil.

Temperature and Humidity

This plant can tolerate below-freezing temperatures in the winter, down to about 15°F (-9°C). They prefer mild climates and coastal areas where the air circulates and keeps things a little cooler. Hot weather stresses them, but they are fairly sturdy, so as long as they get enough water, they should be fine in the summer. 

In terms of humidity, they do grow, as I mentioned, in coastal areas. They like moderate amounts of humidity. Basically, they like weather that is ideal overall. If it’s 60°F (16°C) and sunny with a moderate amount of humidity, they will be happiest.  

Fertilizing

As long as you plant in acidic soil, your heath won’t need much fertilizer. In an alkaline environment, the nutrients won’t break down into a usable form. Top dressing with compost or manure can help to lower the pH of your soil. 

If you end up with a nutrient issue because of alkaline soil, you can fertilize in the spring with an ericaceous fertilizer. This is a formula made specifically for this family of plants. Once a year should be enough. 

Maintenance

An annual application of mulch is great for your Irish heather. It will help acidify the soil and hold moisture. Pine bark is good for plants that need a lower pH. 

You can prune this evergreen, but never prune it back to old wood, as it will not regenerate from that point. A light trim once per year will help it to stay thick and lush. Wait until the flowers fall, and then trim off the tops of the spikes. 

If you wind up with heath that has a woody, scraggly base, you can drop it to make it look better. To do this, wait until spring and dig it up. Dig the hole deeper and drop the plant down so that two-thirds of it is below the soil level. Then, backfill and firm the soil. 

Apply a mixture of 50% grit and 50% coco coir around the stems and firm it as well. Only the top shoots should be visible. Continue to water it and care for it throughout the summer. In the fall, gently lift it out of the ground. Roots should form on the bottom of the shoots. 

Cut the shoots away from the parent plant with roots attached. You can place the new small plants in pots by themselves to strengthen them. You can also pop them right back into the ground.

Propagation

You can propagate Irish heath by cuttings or by layering. The favored method is usually layering, as this seems to be the most consistently successful.

Layering

The most effective way to propagate your heath, and any type of heather, is by layering. To do this, select a branch or branches that are healthy and flexible. Dig a shallow trench where the branch touches the ground if you bend it over. You’ll need a peg to secure the branch to the ground.

To encourage roots to grow, gently score the branch in a spot where it will be underground. The tip needs to protrude from the ground, so make sure not to score too close to the end. Then, bend the branch into the trench and pin it in place. Make sure that the scored section is under the soil when you fill the trench back in.

Continue to water your plant through the spring and summer, keeping the soil consistently moist. In early fall, dig up your stem and cut it away from the plant below where the roots have appeared. They should grow from the scored space on the stem.  Now you have a baby plant!

Cuttings

Propagation by cuttings is fairly straightforward, as well. Do this in the spring once the plant has put on some new growth. Select a healthy branch or branches and take cuttings of about four to six inches. Remove the leaves from the bottom half and dip this end in a rooting hormone. 

Now, you can root these cuttings in soil or water, but water is faster. You can also monitor the process better if you use water in a clear container. Drop the cut end into your container of water, and make sure to refresh the water every so often. When the roots reach about two inches long, you are ready to plant it in its own pot. 

If you prefer to root your cuttings in soil, that works as well. Fill a small container with moist, loose potting medium. Rooting or starting mix works well. Make a hole in the soil, a pencil eraser makes an appropriately sized hole. Then, stick the cut end into the soil and firm it around the base. 

Cover the cutting with plastic wrap or a container that holds in humidity. Place it in a warm spot, out of direct sunlight, and allow it to grow. It will take a couple of months for the roots to develop enough for transplanting. 

Common Problems

Irish heath and others of its relatives are tough plants that rarely suffer from pest infestation or disease. Aphids are the most common pest to affect them. You can deal with these by washing them off with a steady stream of water or using neem oil. Avoid using neem oil when flowers are present, as it will harm pollinators in addition to nuisance insects. 

In warm climates, your plant will be more susceptible to phytophthora root rot. This is a fungal issue that stems from waterlogged soil and an overly humid environment. You won’t likely recognize it until it’s too late to fix the issue, so it’s important to avoid overwatering. An affected plant will show yellowing foliage that eventually drops off, and eventually, it will die. Avoid this issue by improving your drainage before planting and maintaining good watering habits. 

Common Alternative

There is another plant that you may run into when looking for Irish heath. Erica erigena is also given this common name. It is in the same family, looks similar, and requires similar care. It also has a similar range. You can basically treat the two in the same way!

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