Bloomin Designs NurseryStaff Answer
Sep 15, 2026 - 02:02 PM
Hi there,
Thanks for reaching out to us at Bloomin Designs Nursery! Teak containers are a gorgeous choice for perennials, and Heuchera 'Timeless Treasure' PP31987 will look stunning spilling over those edges.
Planting Soil & Coast of Maine Recommendation Coast of Maine Bar Harbor Blend is an outstanding, premium potting soil. Its blend of compost, peat, and perlite holds moisture well while providing solid organic nutrients. Because Heuchera (Coral Bells) are native to rocky slopes and stream banks where drainage is sharp, they despise "wet feet" during winter. To keep crowns from rotting, amend the Bar Harbor Blend with roughly 15–20% extra coarse perlite or pumice to maximize aeration and drainage in those 12.5-inch-deep containers. Always ensure the containers have open drainage holes at the base.
Plant Spacing & Quantity Your containers measure 13.5" x 45.5", giving you just over 4 square feet per planter.
- Spacing: 'Timeless Treasure' matures at roughly 8–10" tall with a 12–14" spread.
- Recommendation: Plant 4 plants per container (placed roughly 10–11 inches apart in a staggered single or slight zig-zag row) for a lush, balanced look that allows room for crowns to grow over the next few seasons. If you want an immediate, dense mass planting right out of the gate, you could place 5 per container, but 4 is ideal for long-term health.
- A single (20) Count Deep Cell Flat (each cell is 4.5" deep) gives you plenty of healthy, deep-rooted stock to fill both planters with extras to tuck into nearby garden beds.
Is 'Timeless Treasure' the Longest Blooming Coral Bell? Yes, it is one of the absolute best rebloomers available. Bred as part of the 'Timeless' collection, it continuously sends up rose-pink flower wands from early summer right through late summer, significantly outlasting traditional single-flush varieties.
Winter Survival on the Cold Side of the House (Zone 7a) Heuchera 'Timeless Treasure' is cold hardy down to USDA Zone 4. In container gardening, roots miss out on the earth's natural thermal insulation, effectively shifting your hardiness zone by about two zones. Since Zone 7a behaves more like Zone 5 in an above-ground planter, 'Timeless Treasure' has plenty of built-in cold tolerance to easily survive winter.
- Site conditions: The "cold side" of the house typically means north- or east-facing exposure. This variety thrives in part shade to dappled light, so morning sun with shade during hot afternoons is perfect. In deep, dense shade, blooming will be reduced. Keep watering minimal during freezes to prevent saturated root systems.
Pros, Cons & Alternative
- Pros: Exceptional continuous rebloom, compact mounding habit, pewter-veined foliage with purple-tinted undersides, and cold hardiness well beyond Zone 7a.
- Cons: Sensitive to crown rot if drainage slows; will need occasional division every 3–4 years as rootstocks mound upward.
- Alternative: Heuchera 'Caramel' PP16560 or most any Heuchera villosa. While they have different bloom windows, their villosa parentage offers bulletproof heat/humidity resistance, though neither matches the persistent rose-pink rebloom cycle of 'Timeless Treasure'.
Happy planting and let me know if you have any questions about prepping your containers!
