Borage in Zone 10A — Southern California

Borage is a fantastic addition to any Southern California garden. Its star-shaped blue flowers not only add beauty, but they also attract beneficial pollinators. Plus, the leaves and flowers have a refreshing cucumber-like flavor, perfect for summer salads and drinks in our warm climate.

While we face drought and occasional heat waves here in SoCal, Borage's long growing season and relatively easy-going nature make it a worthwhile choice. With our 349-day growing season, you've got plenty of time to enjoy this herb.

You can transplant Borage seedlings outdoors from early to late January here in Southern California. Make sure you harden them off first by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space the seedlings about 12-18 inches apart to give them room to grow. Keep an eye on the weather during this time; even though our winters are mild, a surprise cold snap can still happen.

Direct sowing Borage is super easy and often the preferred method here. You can sow seeds from mid January through late October in Southern California. Borage is very generous in our climate, and will self-seed readily.

Prepare the soil by loosening it and removing any large clumps. Borage isn't too picky, but well-draining soil is always a plus. Sow seeds about ½ inch deep and space them 12-18 inches apart. Keep the soil consistently moist until the seedlings emerge.

Borage needs moderate watering here in Southern California. While it's not drought-tolerant, it's also not a fan of soggy soil. Finding the right balance is key, especially with our water restrictions.

During the cooler months, when we get more rainfall, you might only need to water once a week, if at all. In the summer heat, especially inland, you'll likely need to water every other day, or even daily, depending on how hot it gets. Always check the soil moisture before watering. Stick your finger about two inches deep; if it feels dry, it's time to water. Aim for about 1 inch of water per week, adjusting for rainfall.

Water at the base of the plant rather than overhead, especially during our more humid periods, to help prevent fungal issues. If the leaves start to droop, you're likely underwatering. Yellowing leaves can indicate overwatering. Adding a layer of mulch around the base of the plant will help retain moisture in our dry climate.

Your first Borage harvest should be ready around mid March if you plant early. You can continue harvesting through early January, taking advantage of our long growing season. Look for the star-shaped blue flowers to be fully open.

The young leaves are also edible and have a mild cucumber flavor. To harvest, simply snip off the flowers or leaves with scissors or your fingers. Regular harvesting encourages more flower production. As late December approaches and our first frost is on the horizon, harvest any remaining flowers and leaves, or let the plant self-seed for next year's crop.

Here are a few common problems you might encounter with Borage in Southern California:

Self-Seeding Aggressively

• What it looks like: Borage popping up everywhere in your garden, even where you didn't plant it.
• What causes it: Borage is a prolific self-seeder, especially in our mild climate. The seeds readily germinate, leading to unwanted seedlings.
• How to fix/prevent it: Deadhead flowers before they go to seed. If you want to save seeds, collect them intentionally. Remove unwanted seedlings promptly.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes flowers. Leaves may curl, yellow, and die.
• What causes it: This fungus thrives in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it, which can be common in our SoCal gardens.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is also surprisingly effective.

Can Become Leggy

• What it looks like: Long, spindly stems with fewer leaves, especially towards the base of the plant.
• What causes it: Insufficient sunlight or overcrowding.
• How to fix/prevent it: Ensure your Borage gets at least 6 hours of sunlight per day. Thin out plants if they're too crowded. Prune back leggy stems to encourage bushier growth.

Southern California Specific Challenges: Our hot, dry summers can stress Borage, making it more susceptible to powdery mildew if watering isn't managed well. Santa Ana winds can also dry out the soil quickly, requiring more frequent watering.

Borage makes a great companion plant for several vegetables and fruits in Southern California gardens. Plant it near tomatoes and squash; it's said to deter tomato hornworms and squash bugs. It's also a good neighbor for strawberries, supposedly improving their flavor and yield.

Cucumber also benefits from being planted near Borage. I would avoid planting Borage near fennel, as they can inhibit each other's growth.