It’s the beauty of mahonia’s large, blue-green, hollylike leaves that makes this shrub so useful in the landscape. These are some tips on how to incorporate it into your garden.
1. Pick the right variety for your climate
- Oregon grape holly, native to the forests of the Pacific Northwest, has reddish spring leaves that bronze with winter’s cold. Routine thinning of old canes in winter will maintain its size.
- Leatherleaf mahonia lends a strong architectural presence to the landscape. Its large leaves are held at a stiffly horizontal angle from the stems. It’s hardy to Zone 7.
2. Give them the right planting site
- Mahonias perform best if you find a shady, sheltered spot. That way, they won’t be scorched by sun or whipped by winter winds.
- Place them along a house foundation, in front of a hedge or near a wall. Any place they’ll receive a few hours of morning sun but shade from midday onwards is good.
- Nestle these stiffly upright plants among other shrubs, such as barberry and camellia, or with shade-loving perennials, like ferns and hostas.
- Mahonias are also stunning when underplanted with pachysandra, lamium or other shade-tolerant ground covers.
3. Plant them in friendly soil
- Plant container-grown plants in either fall or spring, in holes that are the same depth as the nursery containers but twice as wide.
- To plant, enrich the soil in the hole with compost or leaf mold. Set plants at the same depth at which they grew in their containers. Fill in the hole and water well.
- Mulch with a five centimetre (two inch) layer of shredded bark or pine needles to keep the soil moist.
- After their first season, mahonias become drought tolerant.
4. Don’t be afraid to prune
- These tough plants have few pest or disease problems but may need pruning every other year to help maintain their vigour.
- In winter, lop off the oldest canes, cutting them close to the ground.
- You can remove up to one-third of the canes at a time.
- Never prune mahonia by cutting off the stem tips. You may remove the best foliage, along with flower buds and all chances of seeing fruit develop.
A group of mahonias, or a single one flanked by azaleas or ferns, makes a dramatic picture and requires little expertise. If you plant them in the right spot, and in the right soil, mahonia may grow with little help on your end.