Yellow barrenwort 'Sulphureum'
Epimedium x versicolor 'Sulphureum' ·
The toughest barrenwort: sprays of pale yellow flowers in spring over leaves that open bronze-red and stay nearly evergreen. It tolerates the driest shade.
- Size
- 12 in tall, 18 in wide
- Zones
- 5 to 9
- Light
- Part shade to shade
- Flowers
- Late April to mid May
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around yellow barrenwort 'Sulphureum'
The planner designed this bed around yellow barrenwort 'Sulphureum' when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, part shade. It chose the other plants from the 513 that suit those conditions, and says below why yellow barrenwort 'Sulphureum' stands where it does.
The plants
- 1 Yellow barrenwort 'Sulphureum' × 8, yellow
- 2 Bellflower 'Dickson's Gold' × 19, blue
- 3 Turtlehead 'Hot Lips' × 5, pink
- 4 Japanese meadowsweet × 3, pink
- 5 Dwarf English boxwood × 1, dark green leaves
- 6 White wood aster × 3, white
- 7 Snowdrop × 7, white
- 8 Grecian windflower × 10, blue
Why this plant
- The only airy sprays. The others are open bowls, spires, plumes and others. Shape reads at a distance, where colours blur.
- The only yellow. The one hot colour: every other flower here is cool or neutral.
Why here
- On the front edge. At 12 in it frames the bed without hiding it, and it is in leaf all season. It finishes 58% of the edge.
- 8 plants in 2 runs (5 and 3). Runs of different lengths make the edge a frame, not a ruled line.
Why now
- In flower for four weeks. From late April to mid May.
- Fills a gap. For two of those weeks nothing else on the plan is in flower.
Planned as an English border: 8 of the 8 groups (100%) are drifts, longer along the bed than they are deep. Bellflower 'Dickson's Gold' repeats along the bed to tie it together. There is more bellflower 'Dickson's Gold' than anything else, 19 plants in all.
The planner's own design check: 12 Excellent, 5 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 yellow barrenwort 'Sulphureum' goes in a border
At 12 in it belongs at the front of a bed. In the planner's ten height classes it is low (6 to 12 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
Slower than ivy or pachysandra but far better behaved, and one of the few quality groundcovers that copes with dry, root-filled shade. Plant closely and be patient for two years.
- The most difficult dry shade
- Under maples and beeches
- Slow, weed-proof groundcover
What to plant with yellow barrenwort 'Sulphureum'
Plants recorded as good partners for it, and what each pairing does:
- Lenten rose: purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for three weeks; bold leaves against its medium ones.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; tall enough (20 in) to stand behind it.
- Solomon's seal: in flower together for three weeks, from early May; tall enough (3 ft) to stand behind it.
Questions about yellow barrenwort 'Sulphureum'
Does yellow barrenwort 'Sulphureum' need sun or shade?
Yellow barrenwort 'Sulphureum' grows in part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells.
What zones does yellow barrenwort 'Sulphureum' grow in?
USDA zones 5 to 9. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does yellow barrenwort 'Sulphureum' flower in my zone?
In zone 5 it flowers late April to mid May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 5 | Late April to mid May |
|---|---|
| Zone 6 | Mid April to early May |
| Zone 7 | Mid April to early May |
| Zone 8 | Early April to late April |
| Zone 9 | Late March to mid April |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should yellow barrenwort 'Sulphureum' be planted?
12 in (30 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.
It grows 12 in (30 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many yellow barrenwort 'Sulphureum' plants do I need?
At 12 in apart, set out in staggered rows:
- 12 to fill 10 square feet (about 1 m²)
- 11 for a single row 10 ft (3 m) long
- 38 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as threes and fives, along the front and just behind it.
In the bed above, the planner used eight in two groups.
Is yellow barrenwort 'Sulphureum' poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like yellow barrenwort 'Sulphureum'?
Yellow barrenwort 'Sulphureum' is not native to North America. These North American natives come closest to doing its job:
- Foamflower: the same job in a bed, the same size and the same flowering time; white, not yellow, wants moist soil.
- Creeping woodland phlox: the same job in a bed and the same flowering time; 4 in shorter, blue, pink or lavender, not yellow.
- Green-and-gold: the same job in a bed and the same colour; 6 in shorter, flowers late April to mid June.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
What flowers after yellow barrenwort 'Sulphureum'?
Yellow barrenwort 'Sulphureum' is over by mid May. These start as it finishes and carry the same spot on, so it never goes flat:
- Sweet woodruff: from early May to early June, 8 in tall, to stand in front of it and cover its fading stems.
- Lady's mantle: from late May to early July, 18 in tall.
- Columbine: from early May to mid June, 24 in tall.
What does yellow barrenwort 'Sulphureum' look like in winter?
Yellow barrenwort 'Sulphureum' 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 Epimedium
- Barrenwort 'Amber Queen' Epimedium 'Amber Queen'
- Barrenwort 'Frohnleiten' Epimedium x perralchicum 'Frohnleiten'
- Barrenwort 'Lilafee' Epimedium grandiflorum 'Lilafee'
- Orange barrenwort Epimedium x warleyense
- Red barrenwort Epimedium x rubrum
- White barrenwort 'Niveum' Epimedium x youngianum 'Niveum'
In these guides
Every fact on record
- Type
- Perennial
- Size
- 12 in (30 cm) tall, 18 in (45 cm) wide
- Plant
- 12 in (30 cm) apart
- Height class
- Low (6 to 12 in)
- Place in the bed
- Front
- Flowers
- Late April to mid May; airy sprays; yellow
- Leaves
- Medium texture, semi-evergreen; green
- Shape
- Mounding, spreading
- Hardy in
- USDA zones 5 to 9
- Light
- Part shade, shade
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
Checked against NC State Extension. 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.