Plectranthus ‘Magic Mona Purple’: The purple perennial for shaded balconies

While geraniums, petunias and fuchsias are beginning to flag in August, a comparatively little-known plant is only just getting started: Plectranthus ‘Magic Mona Purple’, often sold as ‘Mona Lavender’. Native to South Africa, it grows in a compact shape, thrives on partially shaded balconies and turns plain hanging baskets into dense globes of purple flowers just as most summer bedding plants have given up.

Why this purple perennial transforms balcony planters

Most traditional balcony plants are strictly seasonal performers: lavish in May, tired by August and finished in September. This is especially true in planters and hanging baskets, where compost dries out and overheats quickly. That is precisely where Plectranthus ‘Magic Mona Purple’ comes into its own.

This perennial densely fills planters and hanging baskets, beginning its main flowering display only when many other plants are already fading.

The plant develops an upright, bushy habit. Depending on its care and pot size, it reaches around 60 to 70 centimetres in height and a similar spread. Rather than producing long trailing shoots, it forms a dense, rounded cushion-like bush that fills the entire container. This makes it ideal for taller hanging baskets, balcony boxes set at railing height and larger pots.

Its foliage is particularly striking: dark green on the upper surface, with a distinctly purple underside. This two-tone look remains eye-catching even before any flowers appear. For this reason, many gardeners deliberately use it as a foliage plant in shady corners too.

Autumn flowers instead of late-summer disappointment

Its real strength is the timing of its main flowering period, which falls in autumn. By the time geraniums and petunias have been deadheaded repeatedly and are half dried out, Plectranthus ‘Magic Mona Purple’ produces long, slender flower spikes in rich purple. They rise clearly above the foliage, creating a bold contrast with the dark green leaves.

The flowers contain plenty of nectar and attract bees and other pollinators, provided temperatures remain suitable. It is therefore a plant that offers both visual appeal and a food source for anyone wanting to make their balcony more wildlife-friendly.

• Flowering period: chiefly late summer to autumn
• Flower colour: purple, carried on long, airy spikes
• Foliage: dark green with purple undersides and a slight sheen
• Height: around 60–70 cm, with a compact, bushy habit

The best position: partial shade rather than blazing sun

Plectranthus ‘Magic Mona Purple’ originates from frost-free parts of South Africa, where it grows in relatively sheltered, partially shaded settings. It is consequently well suited to balconies that are less favourable for traditional sun lovers such as geraniums.

A bright position without full sun is ideal – for instance, an east- or north-facing balcony, or a spot beneath a roof overhang.

It does not cope well with direct midday sun in high summer. Its leaves may scorch, while the compost dries far too rapidly. Anyone with only a south-facing balcony should provide shade, perhaps with taller plants positioned in front of it or a sunshade.

Temperatures and winter hardiness

In mild, almost frost-free regions of the world, Plectranthus grows as a true perennial that can remain outdoors all year. In Central Europe, however, it is frost-sensitive and should be treated as a container-grown perennial that is not winter-hardy.

• Outdoor growing season: roughly May to October, once night frosts are no longer expected
• Frost limit: around 0 °C; ideally, bring it indoors before this point
• Overwintering: keep it bright, frost-free and fairly cool, with less watering

Many home gardeners give the plant a “double life”: a lush balcony or patio specimen in summer, followed by a decorative houseplant at a bright window during winter.

Planting Plectranthus ‘Magic Mona Purple’ in hanging baskets and pots

A successful start depends above all on choosing a suitable container with good drainage. This perennial strongly dislikes waterlogging, as constantly wet roots can easily rot.

• Choose a container: use a hanging basket, hanging planter or pot with several drainage holes.
• Add a drainage layer: place expanded clay pellets or coarse gravel in the base, for example.
• Prepare the compost: combine good-quality multipurpose compost with a little compost and an open, free-draining addition such as expanded clay or perlite.
• Plant it: water the rootball thoroughly, then set it at the same depth at which it was growing in its nursery pot.
• Water in: moisten the compost without soaking it through.

One plant per hanging basket is generally enough, as it branches quickly and will gradually occupy the whole space. In larger containers, two or three plants can be used, optionally alongside understated companions such as white-flowering Bacopa or delicate ornamental grasses.

Everyday care: less demanding than petunias and similar plants

Anyone who has grown petunias or fuchsias will know the routine: frequent watering, generous feeding and continual deadheading. By comparison, Plectranthus ‘Magic Mona Purple’ is pleasantly undemanding.

Watering and feeding

Keep the rootball evenly and lightly moist, but never sodden. Compost in hanging baskets dries out faster, so daily watering is often essential during hot spells; on cooler days, much less is usually required.

It is better to water little and often than to completely flood the pot at irregular intervals.

Applying a liquid fertiliser for flowering plants every two weeks throughout the growing season supports healthy growth and abundant blooms. If controlled-release fertiliser is mixed into the compost, feeding intervals can be extended.

Pruning and shape

Although the perennial branches well naturally, it benefits from occasional “pinching out”: lightly cutting back the shoot tips in spring and after the main flowering period keeps its habit compact and encourages even more side shoots. This produces a uniformly dense, rounded bush in a hanging basket, without bare patches.

Keeping the plant for years and propagating it easily

Although it is not frost-hardy, there is no need to buy a new plant every year. By planning ahead for winter and perhaps taking cuttings, you can build up your own small Plectranthus collection.

Overwintering indoors

Move the pot indoors, or into an unheated but bright stairwell, before the first frost is expected. Temperatures between 5 and 15 degrees are ideal. In a warm living room, the plant will continue growing, but it may become slightly leggy, producing longer and softer shoots. A firm cut-back in spring will correct this.

Water sparingly over winter, using only enough to prevent the rootball from drying out completely. No fertiliser is needed at this time.

Taking cuttings: new plants at no cost

Plectranthus ‘Magic Mona Purple’ is very easy to propagate from tip cuttings. A healthy, well-grown parent plant can quickly provide several young plants.

• Cut shoot tips measuring around 8–10 centimetres long.
• Remove the lower leaves, leaving only 2–3 leaves at the top.
• Insert the cuttings into seed compost or loose multipurpose compost.
• Keep the growing medium lightly moist, but do not allow it to become waterlogged.
• Place them somewhere warm and bright, away from direct midday sun.

After a few weeks, roots will have formed and the young plants can be moved into individual pots. This makes it possible to plant up shaded balcony areas attractively, permanently and inexpensively.

Who benefits most from Plectranthus ‘Magic Mona Purple’?

This purple perennial is especially appealing to home gardeners who have had little success with conventional sunny-balcony plants, or who want to brighten shadier spots. It also generally suits people with busy working lives who cannot manage an evening watering round every day, provided its position is not too hot.

It is equally interesting for anyone wishing to plant their balcony in a more nature-focused way. Its late flowering season fills a gap in the food supply for pollinators, which is a particular advantage in urban areas.

For gardeners who enjoy combining plants, Plectranthus can be paired with other late-summer stars, such as white autumn asters in pots, ornamental grasses or suitably coloured Heuchera. The result is a container arrangement that stays attractive well into October without demanding a daily care schedule.