Gardening 101: Nasturtium

Nasturtium, Tropaeolum majus: “The Rambler”

Is this the prettiest edible plant? With its high-low appeal, nasturtium fits in anywhere that’s relaxed. A vegetable plot near the back door is the obvious place to grow these annuals: the petals, leaves, and seed pods can all be put to good use in the kitchen. There’s no easier way to add color and flavor to a salad than by adding a few of the slightly peppery vermilion flowers.

Above:  Photograph by Jason Ingram. For more, see Required Reading: Kitchen Garden Experts.

With their fiesta colors and devil-may-care attitude toward hot temperatures, nasturtiums tell us they are from southern climes. But they translate well into any garden. First brought back from Central and South America, the nasturtium is half-hardy and requires full sun. It also likes moisture, but the soil must be as well-drained and nutrient-free as you can manage.

Above: Nasturtiums cascade down the facade of the Isabella Stewart Gardner Museum. Photograph by Siena Scarff.

Whether climbing, trailing, or scrambling, nasturtium deserves a prominent spot in the garden in mid to late summer as it attracts so many insects. Bees, hoverflies, and other pollinators are an obvious bonus, but ladybugs will also feast on the stalks, where clusters of black fly tend to congregate. Nasturtiums keep the garden buzzing.

Above: Nasturtiums run wild in Sheila Bonnell’s Cape Cod garden. Photograph by Matthew Williams for Gardenista.

Cheat Sheet

• Nasturtiums tend to wake up after the summer solstice, and cover as much ground as possible as the days grow shorter.
• Some nasturtium varieties repel white fly; others attract black fly (as well as cabbage caterpillars).
• A hard-working companion to cabbage, broad beans, tomatoes, and cucumbers.

Keep It Alive

• Nasturtiums will grow extravagantly as far as the space allows.
• When the weather cools, watch for frost warnings or these glorious plants will turn to mush overnight. (Nasturtiums should really be cut down before this stage, if you can bear it.)

Above: Part of tonight’s salad. Photograph by Kendra Wilson.

It’s possible to grow compact varieties of nasturtium in cream and pale yellow, but that seems to be missing the point. The glorious spectrum of orange, yellow, and crimson lifts the garden during the dog days of summer.

Recommended varieties are N. ‘Alaska’, the yellow-and-orange climber with speckled leaves; ditto ‘Jewel of Africa’. For trailing, try ‘Tip Top Mahogany’, with its tomato-soup-red flowers and bright green leaves. ‘Empress of India’ is more sultry, with darker red flowers and blueish leaves, while elegant ‘Black Velvet’ ticks the boxes for color fanatics: It is dark brown and a wonderful complement to everything.

Above: Nasturtiums mix with other Edible Flowers in Salad; see Kendra’s recipe.

When pickled, the globular seed pods of nasturtium resemble capers; dried, they can be used as a pepper substitute for the imaginative cook. For more ideas, see Foraging with the Vicomte. If left to ripen on the plant, the seed pods should gently self-sow and guarantee a crop the following year, depending on the USDA growing zone.

For more nasturtiums, see DIY: Add Edible Flowers to Your Salad and Garden Visit: The Isabella Stewart Gardner Museum. And browse our Field Guide archives for more summer flowers, including Lavender, Hydrangeas, and Alyssum.

Finally, get more ideas on how to successfully plant, grow, and care for nasturtium with our Nasturtium: A Field Guide.

Interested in other annuals for your garden? Get more ideas on how to plant, grow, and care for various annuals with our Annuals: A Field Guide.

Finally, get more ideas on how to plant, grow, and care for various vines and climbers with our Vines & Climbers: A Field Guide.