Most of us can claim to have grown a nasturtium or two by about age six, as their large seeds make them a favourite “day-care project” (along with beans and sunflowers), and because they germinate so quickly (in 10 to 14 days)— presumably before budding young horticulturists lose interest. But familiarity shouldn’t breed contempt: These annuals have handsome, shield-shaped leaves and bear unique, helmet-shaped flowers in hot, vivid, carnival colours.
'Empress of India' photography by Michael Davis
Plant profile: Nasturtium
Nasturtiums belong to the genus Tropaeolum (meaning “trophy”), which comprises about 85 species that are indigenous to the mountainous regions of Central and South America. Forms of our common garden nasturtium— T. majus, a South American native found from Colombia to Bolivia—have been grown and selected in the Americas and Europe for more than 350 years.
'Strawberry Cream' Blend photography by Millette PhotoMedia
All of the plant (except the root) is edible plant, and there’s no doubt our ancestors looked upon nasturtiums primarily as food: The common name giving a nod to the unrelated genus Nasturtium, which we recognize as watercress.
Immature seed pods pickled in vinegar are a delicious substitute for capers. Simply wash nasturtiums in salted water before eating.
Alaska series photography by Jerry Pavia
Grow nasturtiums together with other annuals and tender perennials that bloom in the same colour palette and that will tolerate the same lean growing conditions, such as:
- ‘Fiesta Gitana’ dwarf Calendula (Calendula officinalis Fiesta Gitana Group) Annual
- Chocolate Cosmos (Cosmos atrosanguineus) Zone 8
- ‘Yellow Flame’ Gazania (Gazania ‘yellow Flame’ [Big Kiss Series]) Annual
Whirlybird series photography by Millette photomedia
When growing your nasturtiums in containers, remember to use soilless potting mix or just plain peat moss that’s been well-moistened; the least hint of nitrogen will produce leaves like lily pads, but not a single flower. Like morning glories, nasturtiums manufacture all the food they require through photosynthesis, so lay off the 20-20-20, and simply savour the flavour while enjoying the view!
'Salmon Baby' photography by Veseys seed LTD.
- Sow seeds in situ outdoors in planting beds or containers one centimetre deep in a full-sun location, one week before your last frost date.
- In beds and borders sow seeds in nutrient-poor soil (amend rich soil with sand and peat moss).
- Harvest young leaves and flowers as soon as they’re fully open.