How Can I Use Nasturtiums as Companion Plants?

Nasturtiums (Tropaeolum majus) are among the most versatile and easy-to-grow companion plants in the garden. They are vigorous annual climbers or trailers with bright orange, yellow, and red flowers, and they serve several useful roles: as a trap crop that draws aphids away from vegetables, as a pollinator magnet that increases beneficial insect activity, and as a ground cover that suppresses weeds between crops. They are also edible — both flowers and leaves are used in salads — so even in a productive kitchen garden they earn their space beyond their companion planting value.

Using nasturtiums as a trap crop

Plant nasturtiums at the edges of the vegetable plot or interspersed between bean, brassica, or courgette plants. Aphids — particularly blackfly — are strongly attracted to nasturtiums and will colonise them in preference to many neighbouring crops. Once aphid colonies establish on the nasturtiums, the plants become a concentrated food source that attracts aphid predators — ladybirds, lacewing larvae, and hoverfly larvae — into the garden. These predators then move on to any aphids that have settled on the vegetables. When the nasturtiums become very heavily infested, remove and compost them and replace with fresh plants.

Attracting pollinators

Nasturtium flowers are rich in nectar and highly attractive to bumblebees, honeybees, and long-tongued hoverflies. Growing them near crops that need pollination — squash, cucumbers, beans, courgettes — increases pollinator activity in the area. For maximum nectar production, choose single-flowered varieties rather than the ornamental double-flowered types, whose extra petals restrict access to the nectaries.

Nasturtiums and whitefly

In addition to aphids, nasturtiums attract cabbage whitefly and glasshouse whitefly, functioning as trap plants for these pests as well. In a greenhouse with tomatoes or cucumbers, trailing nasturtiums grown at the ends of beds can concentrate whitefly populations away from the main crop, though this works best as part of a broader integrated pest management approach rather than as a standalone control.