Growing Scarlet Runner Bean: A Complete Profile
By Growing Home Greens Team · August 10, 2026
Scarlet runner bean is a vigorous flowering vine in the same genus as garden beans, but it’s usually grown for its bright red, edible flowers and ornamental value on a trellis rather than for the bean pods, which are edible too but a secondary reason to grow it.
Sowing it
Transplant, starting 2 to 3 weeks before your last frost with two seeds per cell thinned to one plant, or direct-seed after your last frost once soil reaches at least 60°F, sowing 1 inch deep at about 6 seeds per foot. Germination takes just 4 to 7 days at 60-70°F. Space plants 4 to 8 inches apart.
A trellis is not optional
This vine climbs 9 feet or more in a single season, so a sturdy trellis needs to be in place before or right at planting time, not added later once the vine is already sprawling. A nitrogen-fixing inoculant applied at planting, the same kind used on other beans and peas, improves both flowering and pod set.
Harvesting the flowers
For edible flowers, harvest when they show strong color, either as unopened buds or fully open blooms. Unopened buds hold in the refrigerator for 2 to 3 days if not used right away. Left on the vine, the flowers develop into large, edible pods similar to other runner beans, best picked young before they toughen.
Scarlet runner bean has no well-established companion pairings, and nothing it needs to be kept away from. Given its height, it needs a dedicated trellis spot in the Garden Designer, ideally on the bed’s north edge so it doesn’t shade shorter neighbors.
Source: Scarlet Runner Bean: Key Growing Information, Johnny’s Selected Seeds.
Companion planting guide for Scarlet Runner Bean · Find your planting dates
Typically viable in USDA zones 2-11. Not sure your zone? Look it up by ZIP code.
Mature height: 6-9 ft
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
When to plant scarlet runner bean, by zone
Every zone scarlet runner bean grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Apr 29–May 6 | May 27–Jun 3 | Aug 5–Aug 12 |
| 3a & 3b | May 9–May 16 | Jun 6–Jun 13 | Aug 15–Aug 22 |
| 4a & 4b | Apr 24–May 1 | May 22–May 29 | Jul 31–Aug 7 |
| 5a & 5b | Apr 19–Apr 26 | May 17–May 24 | Jul 26–Aug 2 |
| 6a & 6b | Apr 4–Apr 11 | May 2–May 9 | Jul 11–Jul 18 |
| 7a & 7b | Mar 20–Mar 27 | Apr 17–Apr 24 | Jun 26–Jul 3 |
| 8a & 8b | Mar 4–Mar 11 | Apr 1–Apr 8 | Jun 10–Jun 17 |
| 9a & 9b | Jan 25–Feb 1 | Feb 22–Mar 1 | May 3–May 10 |
| 10a & 10b | Jan 9–Jan 16 | Feb 6–Feb 13 | Apr 17–Apr 24 |
| 11a & 11b | Dec 11–Dec 18 | Jan 8–Jan 15 | Mar 19–Mar 26 |
Bloom dates are about 70 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Scarlet Runner Bean plants fit per square foot?
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 6-9 ft.
Varieties worth considering
- Straight-species scarlet runner bean (Phaseolus coccineus): Johnny's Selected Seeds sells it as the plain species; there's no meaningful named-cultivar market beyond it and a white-flowered selection sold occasionally by specialty catalogs. The red-flowered species is what most gardens grow and what most seed racks sell. (source)
Why each variety is listed comes from the source shown next to it. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement. The buy links are separate from those sources: they go to seed suppliers that sell that exact variety, and we may earn a commission on some of them.
Where to buy scarlet runner bean seeds
None of the seed suppliers we list carries scarlet runner bean seeds right now. A local garden center or a specialty seed house is the place to look.
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See it growing
Search YouTube for "growing scarlet runner bean" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
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Growing Scarlet Runner Bean: A vigorous flowering vine in the same genus as garden beans, grown as much for its bright red edible flowers as for the pods themselves.
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