How to grow a common Rose mallow in your garden?

When should I plant the common Rose mallow in the garden?

The common Rose mallow should be planted in the garden in autumn in mild-climate regions, where winters are not too harsh or long, but summers are hot. This allows it to establish well before the summer season. So plant between September and November.

In continental and cooler regions, spring planting, once the last frost has passed, will be preferred. So plant between March and early June.

Hibiscus moscheutos

Planting of the Common Rose Mallow

Location

Common Rose mallow plants are native to marshy areas of the eastern and southern United States. They prefer damp, even waterlogged locations, during their entire growth period (May to September). A location near a water feature would therefore be perfect.

Par contre, ils préféreront une exposition abritée des vents froids, qui risqueraient d’abîmer et de faire tomber précocement les pétales de leurs belles fleurs éphémères.

These common Rose mallow also need sun to flower well. In hot southern regions, a semi-shaded exposure, especially during the hottest hours of the day, will be preferable.

Liking damp soil, it is important to provide a suitable location for the common Rose mallow

Soil

Côté substrat (la terre dans laquelle pousse la plante), l’Hibiscus des marais apprécie qu’il soit fertile, c’est-à-dire riche en matière organique. Il peut même être lourd et argileux. À l’inverse, un sol trop filtrant risquerait de s’assécher trop rapidement.

Au niveau du pH, il aime les sols neutres, voire calcaires.

Au moment de la plantation, n’hésitez pas à mélanger du terreau pour plantes fleuries à votre terre de jardin. Si elle est assez pauvre en éléments nutritifs, pensez à ajouter également du compost bien mûr, du fumier, de la corne broyée ou du sang séché. Inutile d’ajouter des éléments de drainage : l’Hibiscus des marais aime vivre les pieds dans l’eau.

Planting

1. Half an hour before planting, soak your common Rose mallow in a container of water at room temperature. This will allow the root ball to soak up water and will also facilitate removal from the pot.
2. Dig a planting hole about twice as large as the root ball. Prepare the site by removing adventive weeds and any large stones.
3. Remove the common Rose mallow from its pot, then place it in the centre of the hole. Cover with the mix of garden soil and potting soil (plus any amendments if needed). Firm the soil well around the base to ensure it adheres to the root ball.
4. Water well.
5. Apply organic mulch (straw, dead leaves, BRF, plant husks…), which will retain moisture at the base of the plant and limit the appearance of adventive weeds.

If you are growing several plants, space them about 50 cm to 1 metre apart in all directions, depending on the mature width of the chosen variety.

Care for the Common Rose Mallow

Marsh hibiscuses are fairly easy to grow. Make sure they have plenty of water and sunshine!

Watering

It is one of the key points for successful planting of Hibiscus moscheutos. The soil must never dry out. If needed, proceed with plentiful and regular watering, especially from late spring to early autumn. Prefer watering early in the morning or late in the day to reduce evaporation.

In late autumn and winter, when the foliage has yellowed, the soil may dry out a little, in order to better tolerate the cold. Space out the watering, or even stop it in the event of sufficient rainfall.

Fertilisation

Marsh hibiscuses are fairly hungry plants that thrive in fertile soil to flower well. Don’t hesitate to apply fertilisers to stimulate flowering in early spring. Choose a fertiliser rich in potash, but not too rich in nitrogen, or you may see more foliage than flowers. You can also apply wood ash or well-decomposed compost in autumn.

Pruning

In marsh hibiscus, pruning takes place in early spring, possibly in late autumn in regions where frost does not occur. It consists of cutting back the stems to about 5 cm from the soil, to stimulate forthcoming flowering and to maintain a neat, dense habit.

Don’t panic if you don’t see signs of new growth at the start of spring: marsh hibiscus has slow growth and often doesn’t restart until May.

Pests and diseases

Marsh hibiscuses are plants relatively free from pests and diseases.

Overwintering

More frost-tender than their Hibiscus syriacus cousins, our marsh hibiscuses tolerate frosts around -10°C. They can be grown in open ground without issue in Mediterranean or oceanic regions. In colder climates, from north of the Loire and in mountainous regions, marsh hibiscuses will be grown in pots. If grown in the ground, they must imperatively benefit from protection: thick mulch at their base and winter fleece.

Propagation

Marsh hibiscuses propagate very well by cuttings. Do not hesitate to read our dedicated article: How to propagate marsh hibiscus by cuttings?

Sowing is possible, but longer and more uncertain. You will need to wait several years before you can admire the first flowers.

Sowing is possible, but you will need to be patient