Wormwood 'Powis Castle'
Artemisia 'Powis Castle' · Asteraceae
A billowing mound of finely cut, silver filigree foliage, aromatic when brushed. It rarely flowers, so it stays neat.
- Size
- 2½ ft tall, 3½ ft wide
- Zones
- 6 to 9
- Light
- Full sun
- Flowers
- Grown for its leaves
- Pets
- Toxic (mild)
- Job in a bed
- Specimen
A bed built around wormwood 'Powis Castle'
The planner designed this bed around wormwood 'Powis Castle' when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 715 that suit those conditions and its dry soil, and says below why wormwood 'Powis Castle' stands where it does.
The plants
- 1 Wormwood 'Powis Castle' × 1, silver leaves
- 2 Dianthus 'Kahori' × 3, pink
- 3 Sedum 'Lidakense' × 34, pink
- 4 Brown-eyed Susan × 3, yellow
- 5 Wild quinine × 5, white
- 6 Spring starflower × 12, blue
- 7 Schubert's allium × 3, pink
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
Why here
- At the back. At 2½ ft it is seen over sedum 'Lidakense' (4 in) in front of it, and has nothing behind it to hide.
- A step in the back row. Next to wild quinine (3½ ft) and brown-eyed Susan (4 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A feature plant is seen as an object, and needs clear ground around it.
Why now
- Here for its leaves, into winter. They cover the 13 weeks between early March and late November when nothing on the plan is in flower.
Planned as an English border: 4 of the 4 groups (100%) are drifts, longer along the bed than they are deep. Pink runs through the planting: 3 of the 6 kinds grown for their flowers have it. The longest in flower is dianthus 'Kahori': 17 weeks, from mid May to early September.
The planner's own design check: 11 Excellent, 6 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where wormwood 'Powis Castle' goes in a border
At 2½ ft it belongs in the middle of a bed. In the planner's ten height classes it is medium (24 in to 2½ ft).
Its job: specimen. A feature plant with a shape of its own. It stands alone with room around it, and repeats only at a distance.
The best large silver for separating colours that would clash and for making blues and pinks glow. Cut it back in spring, never in autumn, and not into old bare wood.
- A silver foil between strong colours
- Hot, dry, sunny beds
- Softening the base of roses and shrubs
What to plant with wormwood 'Powis Castle'
Plants recorded as good partners for it, and what each pairing does:
- Russian sage: adds the flowers, mid July to mid September; spires rising out of its mound; tall enough (4 ft) to stand behind it.
- Sedum 'Autumn Joy': adds the flowers, mid August to mid October; bold leaves against its fine ones; happy in the same dry soil.
- English lavender 'Hidcote': adds the flowers, late June to late July; spires rising out of its mound; low enough (18 in) to stand in front of it.
Questions about wormwood 'Powis Castle'
Does wormwood 'Powis Castle' need sun or shade?
Wormwood 'Powis Castle' grows in full sun (6 or more hours of direct sun a day).
It wants dry, sharply drained soil, on the lean side, with no feeding, and little watering once settled.
What zones does wormwood 'Powis Castle' grow in?
USDA zones 6 to 9. It is hardy to zone 6, which means it survives winter nights down to about 0 °F (−18 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should wormwood 'Powis Castle' be planted?
3 ft (90 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3½ ft (100 cm), so a group knits into one patch.
It grows 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many wormwood 'Powis Castle' plants do I need?
At 3 ft apart, set out in staggered rows:
- 1 to fill 10 square feet (about 1 m²)
- 4 for a single row 10 ft (3 m) long
- 4 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one, with clear ground around it: a feature plant is seen as an object, and a group of them is a thicket.
In the bed above, the planner used one in one group.
Is wormwood 'Powis Castle' poisonous to dogs and cats?
Yes: mild toxicity to dogs, cats and horses. Can cause vomiting and diarrhoea in pets if eaten.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like wormwood 'Powis Castle'?
These come closest to doing what wormwood 'Powis Castle' does, and no toxicity is recorded for them:
- Arkansas bluestar: the same job in a bed; 6 in taller, 6 in narrower.
- Silver sage: the same job in a bed; belongs at the front, not in the middle, 18 in shorter.
- Juniper 'Blue Star': the same job in a bed; belongs at the front, not in the middle, 6 in shorter.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
What does wormwood 'Powis Castle' look like in winter?
Wormwood 'Powis Castle' holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.
More Artemisia
- Beach wormwood 'Silver Brocade' Artemisia stelleriana 'Silver Brocade'
- Silver mound artemisia Artemisia schmidtiana 'Nana'
- Southernwood Artemisia abrotanum
- White mugwort Artemisia lactiflora
- White sage 'Silver King' Artemisia ludoviciana 'Silver King'
- White sage 'Valerie Finnis' Artemisia ludoviciana 'Valerie Finnis'
In these guides
Every fact on record
- Type
- Perennial
- Size
- 2½ ft (75 cm) tall, 3½ ft (100 cm) wide
- Plant
- 3 ft (90 cm) apart
- Height class
- Medium (24 in to 2½ ft)
- Place in the bed
- Middle
- Flowers
- None: grown for its foliage
- Leaves
- Fine texture, semi-evergreen; silver
- Shape
- Mounding, clumping
- Hardy in
- USDA zones 6 to 9
- Light
- Full sun
- Soil
- Lean, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Asteraceae
Checked against NC State Extension and ASPCA poison lists. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.