Borage is the cheerful blue flower of the Zone 9 garden: a fast-growing annual with star-shaped blooms that bees adore, cucumber-flavoured leaves, and a habit of self-seeding so freely that one sowing can last for years. It is a herb, a flower and a companion plant all in one — and it asks for almost nothing.
Borage is also one of the best companion plants you can grow. Its flowers bring pollinators to the whole garden, and it is traditionally planted near strawberries, tomatoes and squash. Sow it at the edge of a bed and let it do its work.
Zone 9 at a glance
USDA Zone 9 covers the warmest parts of the southern United States, including much of Florida, southern Texas, southern Louisiana, southern Arizona and coastal California. Winters are mild, with average winter lows of 20 to 30°F, and the growing season runs nearly all year.
The average last spring frost in Zone 9 is Jan 30–Feb 15, and the average first autumn frost is Dec 1–15. These are USDA zone averages drawn from NOAA frost records, not exact dates for any one garden — always check your local extension service and the forecast before planting tender crops outside.
| Detail | Zone 9 guidance |
|---|---|
| Average winter low | 20 to 30°F |
| Average last spring frost | Jan 30–Feb 15 (average/range) |
| Average first autumn frost | Dec 1–15 (average/range) |
| Days to germination | 7–14 days |
| Days to maturity | 50–60 days |
| Sowing | direct sow |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 12–18 inches |
| Water needs | moderate |
| Cold tolerance | hardy |
When to plant borage in Zone 9
Sow borage in Zone 9 from September through April, direct-sown where it is to grow. Seeds germinate in 7–14 days and plants mature in 50–60 days to flowering — one of the fastest flower-herbs you can grow. The average last spring frost is Jan 30–Feb 15 and the average first autumn frost is Dec 1–15 — USDA zone averages, not exact dates, so check your local extension service for your own area. Borage is hardy and tolerates light frost, and an autumn sowing will flower through winter and spring in Zone 9. In high summer it fades and sets seed, so let a few plants go to seed and the patch will renew itself in autumn.
Work back from the frost dates rather than from a calendar date: the planting calendar hub gives the Zone 9 picture month by month. The month guides for October in Zone 9 and February in Zone 9 show what else is happening at planting time.
Starting borage in Zone 9
Direct-sow borage where it is to grow — it has a taproot and dislikes transplanting. Sow seed about half an inch deep in prepared beds, keep the soil moist until germination in 7–14 days, and thin seedlings to 12–18 inches apart. Borage grows into a large, sprawling plant a couple of feet tall and wide, so give it room and do not sow it where it will shade smaller herbs. Once borage has flowered and set seed in your garden, volunteers will appear on their own each season — just thin them to spacing and pull any that land where you do not want them.
Soil, spacing, sun and water
Borage needs full sun and well-drained soil with a pH of 6.0–7.0. It tolerates poor soil better than most herbs and will grow in ground that defeats fussier plants — in fact, too much fertiliser makes lush leaves and fewer flowers. Dig in a little compost before sowing, but do not over-feed. Space plants 12–18 inches apart so air can move between them. Water needs are moderate: keep the soil evenly moist while plants are young, then water only in dry spells. Mulch lightly to hold moisture. Borage grows well in a large pot, which also helps contain its self-seeding.
Companion planting
Good companions for borage include tomatoes, peppers, marigolds and cabbage, and borage itself is one of the best companion plants in the garden — its flowers attract bees and other pollinators, and it is traditionally planted near strawberries, tomatoes and squash. Chamomile is another self-seeding flower-herb that shares the Zone 9 bed, and our guide to when to plant chamomile in Zone 9 shows how the two fit the same garden. Rotate annual crops each year, but let borage self-seed where it is happy. The companion planting finder can suggest combinations for your whole bed.
Pests and problems
The common pests to watch for with borage are aphids, slugs and cutworms, though a vigorous plant is rarely troubled. Aphids cluster on young growth — wash them off with water, and remember that borage flowers attract ladybirds and other aphid-eaters. Slugs nibble young seedlings, especially after rain; hand-pick them after dark. Cutworms can sever young seedlings at soil level; a cardboard collar helps.
Harvest and storage
Harvest borage 50–60 days after sowing, picking the young leaves and the blue flowers as they open. The leaves taste of cucumber and are best used young — older leaves are hairy and coarse. Use the flowers fresh as a garnish, in salads, or frozen in ice cubes for summer drinks. Pick little and often, and the plant will keep flowering for weeks. If you want the patch to renew itself, leave a few flower heads to set seed and drop.
Frequently asked questions
When should I plant borage in Zone 9?
Sow from September through April, direct-sown. Seeds germinate in 7–14 days and plants mature in 50–60 days to flowering. An autumn sowing flowers through winter and spring.
Will borage come back next year?
Usually, yes — it self-seeds freely. Let a few flower heads set seed and volunteers will appear on their own each season.
Is borage edible?
Yes — the young leaves taste of cucumber and the blue flowers make a pretty garnish. Use leaves young, since older leaves are hairy and coarse.
Why grow borage if I do not cook with it?
For the bees. Borage flowers are one of the best pollinator plants you can grow, and they bring bees to your whole garden — including your vegetables.