Borage is a cheerful, fast-growing annual with star-shaped blue flowers and cucumber-flavoured leaves, and it is one of the best bee plants you can grow in Zone 10. It self-sows so freely that one sowing can keep a garden supplied for years.
Grow borage for its edible flowers — a classic garnish for drinks and salads — and for the bees, which visit it constantly. The leaves are edible too, with a mild cucumber taste, though they are hairy, so most people use them chopped in cooking rather than raw in salads.
Zone 10 at a glance
USDA Zone 10 covers the warmest parts of the United States — South Florida, the southernmost tip of Texas, coastal Southern California and Hawaii. Winters are mild, with average winter lows of 30 to 40°F, and the growing season runs nearly all year, with frost a rare event rather than a season marker.
The average last spring frost in Zone 10 is Jan 15–30, and the average first autumn frost is Dec 15–31 — and frost is rare in most Zone 10 gardens. 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 10 guidance |
|---|---|
| Average winter low | 30 to 40°F |
| Average last spring frost | Jan 15–30 (frost rare; average/range) |
| Average first autumn frost | Dec 15–31 (frost rare; 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 10
Sow borage in Zone 10 from October through April, direct-sown where it is to grow. Seed germinates in 7–14 days and plants mature in just 50–60 days, so an autumn sowing is flowering by mid-winter. The average last spring frost is Jan 15–30 and the average first autumn frost is Dec 15–31, and frost is rare, so there is no frost deadline — the practical window is the cool and mild months, since borage fades in the hottest weather. Let a few plants set seed and they will self-sow for the next season.
Work back from the frost dates rather than from a calendar date: the planting calendar hub gives the Zone 10 picture month by month. The month guides for October in Zone 10 and March in Zone 10 show what else is happening at planting time. The seed starting calculator can help you work out your exact sowing dates.
Starting borage in Zone 10
Direct-sow borage seed about a quarter-inch deep where it is to grow, spacing plants 12–18 inches apart, and keep the seedbed moist for 7–14 days until it sprouts. Borage has a taproot and dislikes transplanting, so avoid starting it in pots. Thin seedlings to their final spacing, and give plants room — a mature borage plant is large, sprawling and over three feet across. Water young plants regularly until established, then water sparingly; borage is fairly drought-tolerant once it is growing.
Soil, spacing, sun and water
Borage needs full sun in Zone 10 — in the hottest months a little afternoon shade keeps leaves tender and prevents scorch, but too much shade weakens flavour and growth. It grows best in soil with a pH of 6.0–7.0. Borage is not fussy about soil, growing well in ordinary garden soil with a pH of 6.0–7.0. It prefers soil that drains freely, and it does not need rich feeding — too much fertiliser makes leafy plants with few flowers. Space plants 12–18 inches apart so air can move between them; crowded plants stay damp and invite disease in Zone 10 humidity. Water needs are moderate: keep the soil evenly moist, especially while plants are young and in warm weather, and mulch to hold moisture and keep roots cool. A raised bed or a pot with drainage holes is often the easiest way to get the drainage right, so work out how much mix a bed or container needs before you buy.
Companion planting
Good companions for borage include tomatoes, peppers, marigolds, cabbage. Borage is a superb companion plant, listed with tomatoes, peppers and cabbage, and it is traditionally planted near strawberries, squash and tomatoes, where it is said to improve growth and deter pests. Its flowers attract bees and beneficial insects in large numbers, which helps pollination across the whole garden. The October guide for Zone 10 in October shows what else is going in at the same time.
Our guide to when to plant stevia in Zone 10 shows how to time a second crop alongside it. For comparison with a cooler zone, see when to plant borage in Zone 9.
Pests and problems
The common pests to watch for with borage are aphids, slugs, cutworms. Aphids may cluster on soft growth — wash them off with water, or leave them for the ladybirds that borage flowers attract. Slugs can nibble young seedlings in damp weather, and cutworms occasionally cut seedlings at the base. Borage is generally trouble-free in Zone 10 and shrugs off most pest damage. Check the undersides of leaves weekly — most Zone 10 pest problems are small when caught early and much harder once they spread. Avoid spraying broad insecticides on herbs you plan to eat; a strong jet of water, hand-picking and encouraging ladybirds and other beneficial insects will deal with most outbreaks.
Harvest and storage
Start picking borage flowers once plants are in bloom, about 50–60 days after sowing, and pick little and often — regular picking encourages more flowers. Pick the blue star-shaped flowers in the morning, when they are fully open, and use them fresh the same day as a garnish for drinks and salads — they do not keep well. Snip young leaves for cooking, where the cucumber flavour works in soups and stews. At the end of the season, let a few plants set seed and scatter it where you want borage next year.
Frequently asked questions
When should I plant borage in Zone 10?
Sow from October through April, direct-sown where it is to grow. It matures in just 50–60 days and self-sows freely.
What is borage good for?
Its edible blue flowers are a garnish for drinks and salads, its leaves taste of cucumber, and it is one of the best bee plants for the garden.
Will borage come back next year?
Yes — it self-sows very freely. Let a few plants set seed and seedlings will appear on their own next season.
Can I transplant borage?
It is best not to — borage has a taproot and hates disturbance. Direct-sow it where it is to grow.