T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Tropaeolum majus (Nasturtium)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Brassicales
Family: Tropaeolaceae
Genus: Tropaeolum
Species: T. majus
Binomial name: Tropaeolum majus
Synonyms: Cardamindum majus, Nasturtium indicum, Tropaeolum elatum, Tropaeolum hortense, Tropaeolum hybridum, Tropaeolum pinnatum, Tropaeolum quinquelobum, Trophaeum majus.
Common names: Nasturtium, Garden nasturtium, Tall nasturtium, Indian cress, Monks cress. It is not closely related to the genus Nasturtium

Tropaeolum majus is a flowering plant originating in the Andes from Bolivia north to Colombia. However it does not grow in the wild, only being reported from cultivated and naturalised populations. It is thought to be a hybrid between Tropaeolum ferreyrae and Tropaeolum minor, both of which are native to the Andes region in western South America. The species has become naturalized in many countries of the world. In New Zealand it and its cultivars are widely grown gardens but it is also a weed of watercourses, urban bushland, roadsides, railways, gardens, disturbed sites and waste areas. The seeds and stem segments are spread by water and by being dumped in garden waste.

Tropaeolum majus is a short-lived (i.e. annual or biennial) herbaceous plant with prostrate or sprawling fleshy stems growing 0.5-2 m long or more at a fast rate. The stems and leaf stalks are pale green in colour, hairless and somewhat fleshy.
The leaves are large and orbicular in shape (>15 centimetres in diameter) and are a green to glaucous green above, paler below and have several prominent veins radiating to an entire or slightly lobed margin. They are are borne on long stalks that are attach to the centre of their undersides.
The flowers are borne singly in the upper leaf forks on stalks that are 15-25 cm long. They are 2.5–7 cm diameter, with five petals, eight stamens, and five sepals (1-2 cm long) that are fused together at the base. One of these sepals is formed into a nectar-bearing spur (2.5-4 cm long) that is either straight or slightly curved. The flowers colours vary from yellow to orange to red, frilled and often darker at the base of the petals. Flowering occurs mostly in spring, but also in summer and autumn.
The fleshy pale green fruit (about 10 mm long) are split into three-segments, each segment has a single large seed 1–1.5 cm long. The seeds are a pale green in colour and are prominently ribbed on one side.

A few photos of different coloured flowers.\








 


Surface of a leaf.


The underside of a leaf.


A creeping ground cover of Nasturtium at Waiwaka Reserve




Tropaeolum majus starting to smother a camellia