Opuntia humifusa. (Eastern prickly pear cactus)
Opuntia humifusa

Zone: 4 to 9

Soil: Sand

Light: Full sun

Bloom colour: Yellow to slightly orange

Bloom period: Early summer

Height: 2 feet

Moisture: Dry

Attracts: Unassessed

Notes: This cactus is not widely available in stores; it is an endangered species in Ontario; and your neighbours will definitely stop to take a look at this plant if it is growing in your front garden. The flowers should attract bees, but I have not assessed this plant for its wildlife value.

This plant is strange and interesting in so many ways. It does not have leaves. Instead, the plant is made up of stems that swell up with water to form pads. In winter, the plant will look a bit sickly because the pads flatten out and lose water. In the latter part of the spring, the leaves become more succulent and each pad will form buds that grow into new pads on the outer edge. By late June, flower buds, which also grow at the upper edge of the pads, become visible.

The flowers are amongst the most beautiful of any plant in Ontario. The sepals and petals are undifferentiated and are collectively called tepals. Lots of plants form yellow flowers, but the tepals on the Eastern prickly pear cactus have an unusual orange tint to them. The tepals are intricately arranged and surround a tight cluster of bright stamens. The flowers open and close in just one day and it is actually quite disappointing that such an exquisite flower should be so fleeting. However; the next day, another group of flowers will open up to give a blooming season that will last 2 to 3 weeks.

The plant's natural defences can pose a problem when you are planting it. Wear leather gloves and use kitchen utensils to avoid handling any of the pads. The spines are obvious and are long enough to draw blood if you spike yourself on them, but they are not the issue. A cactus pad is covered in areoles, small bumps on the surface from which several spines are growing. Areoles also contain many glochids, tiny "no see um" bristles that are barbed. They become lodged in your skin and if you do not pull them out, the symptoms will progress from painful irritation to dermatitis that can last for months. Any signs of irritation after planting a cactus should be acted upon as soon as possible. Locate the glochids with a magnifying glass and grip them at the base with tweezers to pull them all out.

To replicate its natural habitat, give this plant sandy soil, full sun, no water and no love. It will reward you by growing into a fantastic eye-catching plant at the front of your border.

Opuntia humifusa - Eastern Prickly Pear Cactus
Flower of Opuntia humifusa
These cactus flowers only last one day.
Opuntia areole
The spines are clearly seen growing out of the areole and they are surrounded at the base by glochids.
Areoles on cactus pads
The areoles help the plant defend itself against animals that are seeking alternative supply of water and sugar.
Opuntia with flower buds
The red flower buds grow out of the top of the pads.
Opuntia flower surrounded by tepals
The stamens are surrounded by tepals