One of the most widely grown of all of the wormwoods is Artemesia ‘Powis Castle’. Grown mainly as a foliage plant and regarded as one of the best grey or silver foliage plants of all.
Originating from Wales where is was identified as a distinctive cultivar at ‘Powis Castle’, it carries the name. An evergreen perennial that grows well in sunny positions it will reach around 1m in height.
The foliage is fragrant and is also finely dissected, along with the silvery appearance makes it a most desirable plant for the garden border.
How to Grow Artemisia ‘Powis Castle’
Full sun to part shade and a humus rich soil is best. Artemesia ‘Powis Castle’ will cope with dry conditions however a little mulch to help maintain a cool root run is beneficial. Deep shade is not suitable as the plant tends to become very leggy in these conditions.
Growing Conditions
- Light: Full sun to part shade (best colour in full sun)
- Soil: Well-drained, humus-rich
- Water: Drought-tolerant once established
- Tip: Avoid deep shade — it causes weak, leggy growth
- Add mulch to keep roots cool and retain moisture
- Minimal watering once established
- Great for borders, Mediterranean-style gardens, and contrast planting
How to Prune Artemisia ‘Powis Castle’ and other species.
Start by removing any dead or damaged wood and then prune back to shape. Can also be tip pruned or pinched back in spring.
Artemisia respond well to pruning, and annual pruning in spring is the easiest method. This can be a fairly compact plant, however over time it will require pruning to maintain shape. For annual pruning, simply use hedging shears or secateurs and prune back about 1/3 of the growth.
It can be cut back in early spring after the danger of frosts haves passed.
The second type of pruning is a little more brutal, and older plants that need rejuvenation can be treated this way. You will notice shoots from the base, and you can prune back hard if the plant has become unruly.
- The time to prune is in late winter to spring, just as the weather warms a little.
- Use a sharp pair of loppers or secateurs and cut the whole plant back to around 6 inches (15cm) above the ground.
- Make sure the cuts are clean to prevent disease and splitting.
- Don’t worry about hard pruning. Most times the plant will bounce back with masses of new growth.
- Fertilise, water and mulch after pruning.
- Follow up with a light pruning mid spring after the plant has put on new growth. This will encourage a bushy better shaped plant.
Design Tips
- Keep good airflow (important for dry-climate plants)
- Avoid overcrowding—these plants prefer breathing room
- Group in odd numbers for a natural look
- Use gravel mulch for a clean Mediterranean style
- Works beautifully in coastal or low-water gardens
Companion Plant Ideas
Colour Contrast (Purples, Blues, Pinks)
These really stand out against the silver foliage:
- Lavandula angustifolia – classic pairing, same dry conditions
- Salvia nemorosa – upright purple spikes
- Nepeta faassenii – soft blue haze, long flowering
- Echinacea purpurea – bold summer flowers
Warm Tones (Yellows & Oranges)
Great for a Mediterranean feel:
- Achillea millefolium – flat flower heads, drought hardy
- Coreopsis verticillata – fine foliage, bright yellow flowers
- Gaillardia aristata – red/orange tones
Texture & Structure Contrast
To balance Artemisia’s softness:
- Stipa tenuissima – light, flowing movement
- Lomandra longifolia – Australian native, strappy leaves
- Westringia fruticosa – compact shrub, grey-green
Structural Anchors (Shrubs)
For a layered look:
- Lavandula dentata
- Rosmarinus officinalis
- Santolina chamaecyparissus
Summary
- Height – To 1 metre ( 3ft )
- Spread – To 1 Metre ( 3 ft)
- Position – Full sun.
- Soil – Humus rich well drained.
- Common names – Wormwood, Silver Sage.
- Foliage – Silvery grey
- Pruning – Prune back inmate winter to spring.
- Drought tolerant – Yes once established.
Artemesia ‘Powis Castle’ is available for sale from the following nurseries
412 James Lane, Fern Hill VIC. 3458 - Phone 0419002651
Large range of Rare plants, Climbers, Bulbs, Perennials Fruit Trees, Ornamental Trees and Shrubs. Available both Retail and by Mail OrderÂ
www.whitehousenursery.com.au
52 Rodd St Canowindra NSW 2804
An online nursery specialising in drought and frost tolerant perennials and fragrant, edible and herbs.
www.perennialle.com.au