How to Grow Euphorbia 'Miner's Merlot'

Sun

Full sun produces the deepest burgundy foliage color. The plant tolerates light afternoon shade, especially in zones 8 and 9 where summer heat is intense, but the foliage turns greener and the chartreuse spring bracts fade faster in shade.

Drainage

Euphorbia 'Miner's Merlot' needs well-drained soil. The roots rot quickly in soggy conditions. Heavy clay is the wrong habitat. Dig a one-foot test hole and fill it with water. If water sits more than a few hours, build a raised mound or amend with coarse sand or grit before planting.

Soil

Average to lean garden soil works fine. Heavily amended beds with lots of compost push the plant into floppy growth at the expense of dense compact form.

Space

Space 18 to 24 inches apart for a ground-cover effect, or single plants give a tight mound shape. The underground spread is slow, so plan on the gaps closing over 3 to 5 years.

Watering

Water deeply once a week through the first growing season to help establishment, soaking the root zone rather than splashing the foliage. Avoid overhead sprinklers, since wet foliage in humid weather invites fungal trouble.

Established plants are drought-tolerant and get by on rainfall in most years. A deep weekly soak through extended summer dry spells keeps the foliage looking fresh, but the plant tolerates real drought better than it tolerates wet feet.

Feeding

Skip the fertilizer. Euphorbia 'Miner's Merlot' grown in lean soil holds its compact form and stays dense. Heavy feeding produces floppy stretched growth and washes out the burgundy foliage color.

Wear gloves and long sleeves

The milky sap leaks freely from every cut and causes skin reactions ranging from mild irritation to chemical burns depending on exposure. Wear sturdy garden gloves and long sleeves anytime you cut or shape the plant. Avoid pruning on hot sunny days when sap flows most readily, and keep sap away from your eyes.

Cutting back spent flower stems

Once the chartreuse spring bracts fade to brown in early summer, cut the spent flowering stems back to the base of the plant. This redirects energy into the burgundy basal foliage rosettes and keeps the clump dense.

Cleaning up winter damage

In late winter, remove any brown or winter-burned leaves at the soil line to make room for fresh growth. The foliage usually holds through winter in zones 7 and warmer, with some scorch on exposed leaves in zone 6.

Spring bract display

The plant produces tall stems topped with showy chartreuse to lime-green bracts in mid to late spring. The display lasts 4 to 6 weeks, gradually fading to brown by early summer. The actual flowers within the bracts are tiny and barely visible, since the colorful display comes from the surrounding leaf bracts.

Year-round burgundy foliage

The basal foliage stays a deep burgundy through summer, fall, and winter in zones 7 and warmer. Color is deepest on plants growing in full sun. In shade, the leaves shift toward green with burgundy edges. Cold winter wind in zones 6 and the cold edge of zone 7 can scorch exposed leaves, which recover with fresh growth in spring.

Cutting for arrangements

The chartreuse bracts make excellent cut flowers for spring arrangements. Cut stems early in the morning when the bracts are at peak color. Sear the cut stem ends in boiling water for about 10 seconds to seal the sap inside the stem, which both prevents wilting and keeps the irritating sap off your hands.

Skin reaction from the sap

Stinging, redness, or blistering after sap contact. Wash the affected skin immediately with soap and water. Cover any cut on the plant with a tissue or rag while working to limit drip. Keep sap away from eyes especially, since eye exposure requires immediate flushing with water and a call to a doctor.

Yellowing foliage and slow collapse

Almost always root rot from wet soil or poor drainage. Pull back watering and improve drainage with sand or grit worked into the area. If the plant is still small, dig it up in spring, build a raised mound, and replant on the mound.

Foliage turning green instead of burgundy

The plant is in too much shade. Move to a sunnier spot in fall while the plant is dormant. Full sun deepens the burgundy color the most, and morning sun with afternoon shade still produces good color in hot zones.

Brown crispy leaves in late winter

Winter burn from cold wind and frozen soil. Common at the cold edge of zone 6 on exposed sites. Damaged leaves drop and are replaced by fresh growth in spring. A burlap wind screen or a sheltered planting spot reduces damage in future winters.

Aphids on new growth

Small green or black insects clustered on stems and new leaves in spring. Knock them off with a strong spray of water. Heavy infestations respond to insecticidal soap. Ladybugs eat aphids faster than any spray.

Scale insects on stems

Small bumps that scrape off with a fingernail, often with a sticky residue beneath them. Wipe each cluster off with a cotton swab dipped in rubbing alcohol. Heavier infestations respond to horticultural oil sprayed in late winter.

Floppy stretched growth with washed-out color

Usually too much fertilizer or too rich a soil. Pull back feeding entirely next season and let the plant grow in lean soil. The compact mounded form returns once the plant is no longer pushed.

Clump not spreading

Spread is slow by design in this cultivar, often only an inch or two per year. Be patient through the first 3 to 4 years. A clump that hasn't spread at all by year 5 usually means the soil is too heavy or too wet, in which case improve drainage at the site.