They can also be used as trap plants to lure aphids away from desirable plants. Some varieties of nasturtiums form a bush; others are trailing.
Their Latin name means "nose twister" because of the way people sometimes react to the peppery, sweet taste. During World War II, the seeds were used as a pepper substitute. Nasturtiums can also be used as trap plants to lure aphids away from desirable plants.
(Nasturtiums and Dahlias in a Basket (1884), Paul Gauguin, public domain)
Nasturtiums can be divided into two main types: trailing or climbing (Tropaeolum majus) and bush or dwarf (Tropaeolum minus). The primary difference is their growth habit. Trailing nasturtiums form long vines, while bush varieties remain more compact.
Trailing nasturtiums are an excellent choice for hanging baskets and window boxes since the vines cascade and climb beautifully. Bush varieties work well in smaller gardens with limited space.
Selecting and preparing the planting site
Nasturtiums do well in soils that are not rich, and they don't usually need additional fertilizer unless the soil is extremely poor. Too much nitrogen encourages more foliage than flowers. Soil must drain well.
Plant nasturtiums where they will receive 6-8 hours of full sun. They will grow in partial shade (3–6 hours of sunlight), but won’t bloom as well.
Know the growth habit of the nasturtium variety you want to grow. You'll usually need supports for trailing types.
When to plant
Nasturtium seeds can be sown directly in the garden or started indoors. However, the roots are fragile and prone to transplant shock. Direct sowing is preferable. Start seeds indoors 2-4 weeks before your last spring frost date. Sow seeds outdoors 1-2 weeks after your last spring frost date. Soil temperatures should be 55° to 65°F (12°-18°C). Always protect young seedlings from late frosts.
How to plant
In the garden, sow the seeds 1/2" deep and 10-12 inches apart. Plants should germinate in 7-10 days.
How to harvest
Flowers and leaves can be harvested anytime. Harvest seedpods before seeds have a chance to mature and harden. To avoid damaging the plant, always use scissors to snip off leaves, flowers, and seedpods.
If allowed to mature, save the chickpea-size seeds to replant next spring. Let seeds dry on the vine and fall off. Clean, dry, and store in a paper envelope in a cool, dark place.
Seeds can also be preserved and pickled like capers.
- ‘Alaska Variegated’ has variegated foliage covered with bright gold, orange, salmon, or mahogany spurred flowers.
- ‘Variegatus’ is a trailing type with red or orange flowers.
- ‘Salmon Baby’ adds a pretty salmon-pink color to the garden.
- ‘Peach Melba’ has creamy yellow flowers with orange-red centers.
Aphids are especially attracted to yellow nasturtiums. Additionally, they may also attract harmful cabbage moths which, in turn, helps protect tender cabbage, kale, and broccoli, as well as other members of the Brassica family.
Nasturtiums can also attract beneficial bugs like hoverflies that eat aphids.
Read more at Gardening Know How: Nasturtium Flowers – How To Grow Nasturtiums https://www.gardeningknowhow.com/ornamental/flowers/nasturtium/growing-nasturtiums.htm