Mona Amethyst Spur Flower

Mona Amethyst Spur Flower (Plectranthus 'Mona Amethyst') is a compact shade perennial that grows to about 60cm tall and wide and holds upright spikes of purple flowers above purple backed foliage. It answers a problem most gardens have somewhere: a shaded bed where nothing will flower. Growth is quick, so a bare strip closes over in a single warm season.

Why you'll love it

• Flowers where sun lovers sulk. It sets purple spikes in bright shade and part shade, so a shaded courtyard or the south side of a fence finally gets colour.
• Colour between flushes. The leaf undersides are purple, so even out of flower the planting reads as more than plain green.
• Fills fast. It branches from the base and grows quickly, so ten plants set at 40cm close into a continuous band within a season.
• Feeds bees and butterflies. The spikes carry real nectar, useful in a small courtyard with little else in bloom.

Where it works best

Shaded borders and edging. Plant 40cm apart in a single row. One pack of ten runs close to 4m of edge, which suits a path or the front of a shaded bed.

Mass planting under canopy. Set at 40cm in a staggered grid it becomes a flowering ground layer beneath established trees, in the shade where lawn gives up.

Pots, balconies and courtyards. One plant fills a 300mm pot and three fill a trough, giving a display on a balcony that never sees direct sun.

Growing Mona Amethyst Spur Flower in Australia

Position and climate. Bright shade to part shade suits it best, and hot afternoon sun bleaches the leaves. This is a plant for tropical, subtropical and warm temperate gardens. It is frost tender, so in cool inland and southern districts grow it in a pot that can move under cover for winter.

Soil. Free draining soil with plenty of organic matter. Dig compost through the bed before planting and mulch about 50mm deep, kept clear of the stems. Cold wet soil in winter causes more losses than cold air does.

Water and feed. Keep the soil evenly moist while it establishes, watering once the top few centimetres dry. A controlled release fertiliser in early spring and a liquid feed each month through the warm season keeps it flowering.

Pruning. Cut it back by about half once flowering finishes. It reshoots readily and stays compact. Left alone it opens in the middle and sprawls over its neighbours.

What to expect when it arrives

It is sold in one size, a pack of ten in 140mm pots. The plants are young and well rooted, which is the stage that establishes fastest and the reason a whole border can go in at once for the price of a few advanced plants. They are packed to travel upright.

Plants are delivered Australia wide, with delivery from $29.95 and a minimum order of $300 before delivery. Expect a quiet fortnight after planting, then new shoots within four to six weeks in warm weather. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Shop plants for part shade
• Ground cover options for shaded beds
• Plants suited to mass planting
• Low growing ideas for garden borders

Common questions

How many plants do I need for a border?

At 40cm spacing a pack of ten covers close to 4m in a single row. For a wider bed, run a second staggered row 40cm behind the first.

Will it flower in deep shade?

Flowering thins in heavy all day shade. Bright shade under open canopy, or a spot with two or three hours of gentle morning sun, gives the best spikes.

Can it handle frost?

No. It is frost tender and a hard frost cuts it to the ground. In cool districts keep it potted so it can shelter through winter.

How do I stop it going leggy?

Cut it back by half after each flowering flush. That one habit is the difference between a dense cushion and an open, sprawling plant.