What hardiness zones is Stachys byzantina suitable for?

A low-growing, mat-forming perennial in the family Lamiaceae, native to the rocky hillsides, open scrub, and dry grasslands of Turkey, Armenia, Iran, and adjacent regions of the Middle East and Caucasus, growing in poor, well-drained, often calcareous soils in full sun. Plants form dense, spreading mats 6–12 inches (15–30 cm) tall and 18–24 inches (45–60 cm) wide of thick, oblong-ovate leaves 3–5 inches (8–13 cm) long densely covered on both surfaces in soft, silvery-white woolly hairs — the defining characteristic that gives the plant its common name. The leaves are thick, soft, and tactile, with an unmistakable velvety texture. From June through July, erect, woolly, square stems 12–18 inches (30–45 cm) tall bear dense whorled spikes of small, tubular, two-lipped flowers in rose-purple to magenta, also covered in silvery wool. The cultivar 'Silver Carpet' produces no flower stems, maintaining a clean foliage mat. Mildly toxic to pets if ingested in large quantities.

Native Range

Native to rocky hillsides, dry scrub, and open grasslands of Turkey, Armenia, Iran, and adjacent areas of the Middle East and Caucasus, growing in poor, well-drained, often calcareous soils in full sun.

Suggested Uses

Planted as ground cover, border edging, and textural contrast in dry gardens, Mediterranean-style plantings, and mixed borders at 12–18 inch (30–45 cm) spacing. The silver-white foliage is one of the most effective contrast elements in the garden — combine with purple salvia, pink roses, lavender, or deep-red heucheras. Outstanding for dry slopes, gravel gardens, and planted seams in paving. The 'Silver Carpet' cultivar is ideal where a clean foliage carpet without flower stem maintenance is wanted.

How to Identify

Unmistakably identified by the dense covering of soft, silvery-white woolly hairs on both surfaces of the thick, oblong-ovate leaves 3–5 inches (8–13 cm) long — producing a velvety, tactile texture unlike almost any other common garden plant. The combination of this distinctive felted-silver foliage, mat-forming spreading habit, and (in flowering forms) erect woolly stems with whorled rose-purple flowers in June–July is diagnostic.

Appearance

Size & Dimensions

Height6" - 1'6"

Width/Spread1'6" - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer

Blooms June through July on erect, woolly stems 12–18 inches (30–45 cm) tall bearing dense whorled spikes of small rose-purple to magenta two-lipped flowers in woolly calyces. The flowers attract bumblebees and wool carder bees, which harvest the leaf wool for nesting material. Many gardeners remove flower stems before they develop to maintain a clean silver foliage mat. The non-flowering cultivar 'Silver Carpet' never produces flower stems.

Detailed Descriptions

Flower Description

rose-purple to magenta; small tubular two-lipped flowers in dense whorled spikes on woolly erect stems; also woolly-haired

Foliage Description

silvery-white; thick oblong-ovate leaves 3–5 inches long entirely covered in dense soft woolly hairs on both surfaces — velvety tactile texture

Growing Conditions

Sun Requirements

Full Sun

Requires 6-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

sand chalk rocky loam

Drainagewell drained

Water & Climate

Water Needs

Very Low

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plant in full sun in lean, sharply drained, neutral to slightly alkaline soil with a pH of 6.0–8.0. Excellent drainage is essential — wet, heavy, or poorly drained soils cause crown rot, particularly in winter. Avoid rich or moist soils; lean conditions maintain the most silvery, compact foliage. Tolerates drought, poor soil, and heat. In the Pacific Northwest's wet winters, ensure very good drainage or the mat will develop dead patches. Thin and divide every 2–3 years to control spread and revitalize the mat.

Pruning

Remove dead or rotted foliage in early spring — pull out brown, matted sections common after wet Pacific Northwest winters. Cut flower stems to the base before or after bloom depending on preference; removing them before elongation keeps the foliage display clean. Divide or thin every 2–3 years in early spring or early fall: lift sections, discard oldest central portions, and replant vigorous edge rosettes at 12–18 inch (30–45 cm) spacing.

Pruning Schedule

early springsummer

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 3 gallons

⚠️ Toxicity Warning

Toxic to pets