How to grow Panicum in pots?

Which Panicum varieties can be grown in pots?

Generally, Panicum plants reach a height of between 1 and 2 metres. Some cultivars of the type species Panicum virgatum offer a more compact growth, not exceeding 1 m in height, particularly suited to small spaces and container cultivation. Among the most suitable varieties:

• The Panicum virgatum ‘Shenandoah’: interesting for its compact growth, reaching around 60 to 70 cm in height in all directions. This variety forms a broad clump with very colourful blue-green foliage shading to burgundy red as the summer progresses, turning coppery and purplish toward the end of the season.
• The Panicum virgatum ‘Sangria’: another variety particularly compact not exceeding 50 cm in all directions at ripeness. It stands out for its green leaves at the base, largely coloured blood red, incredibly striking!
• The Panicum virgatum ‘Blue Darkness’: a cultivar at once compact (no more than 1 m in height at ripeness) and exceptional for the colour of its variegated foliage with deep purple-black and blue-green.
• The Panicum virgatum ‘Cheyenne Sky’: no taller than 80–85 cm in height, this upright panicum displays a sumptuous foliage evolving from blue-green in summer to wine red in autumn.

Panicum virgatum ‘Shenandoah’, ‘Sangria’ and ‘Cheyenne Sky’

Where to plant Panicum in a pot?

To thrive, Panicum requires a warm, sunny exposure. It is in full sun that it will reveal its full splendour. On the terrace or balcony, place your pot in full sun, as This exposure heightens the colour intensity of its leaves. The colour of the foliage becomes even more intense when day–night temperature differences are pronounced.

What type of pot should I choose?

Panicum grows very vigorously, even when grown in a pot. The container must be large enough, as these imposing grasses have a deep and well-developed root system. That is why it is important to choose a pot that is taller than wide (Panicum has roots that grow deep), measuring at least twice the size of the root ball and suited to the mature height of the chosen variety. The bottom of the pot must be perforated to allow watering or rainwater to drain away and to ensure good drainage. You can choose the pot you prefer, noting that terracotta pots provide better root aeration. Being more porous, they will, however, require more frequent watering than plastic pots, which tend to retain moisture.

Which growing medium should I use?

Very adaptable in open ground, Panicum adapts well, showing a preference for calcareous soils that are fairly fertile, deep, and ranging from dry to moist, where it establishes itself best. The most important thing is to plant it in a well-draining substrate. Plant it in a well-draining mix formed of two-thirds universal potting compost and one-third planting sand. For improving this drainage, provide expanded clay pellets or gravel to spread across the bottom of the pot.

Panicum ‘Buffalo Green’ and ‘Hot Rod’ (photos © Plantipp)

When and how to plant it?

You can plant your Panicum in a pot in spring (from February to April–May) or in autumn (September–October). Do this outside frost periods or during extreme heat.

• Moisten the root ball by dipping it in a basin of water
• At the bottom of the large perforated container, spread a drainage layer (about 20% of the pot’s volume)
• Add part of the soil and sand mix until it reaches halfway up the pot
• Install Panicum in the centre of the pot so that the collar sits flush with the top of the pot, without burying the base of the stems
• Fill with the remaining potting mix
• Gently firm with your hand
• Water
• Spread organic mulch to prevent the substrate from drying out too quickly

How to care for a Panicum in a pot?

Watering

Watering will require closer attention for potted plants, where the soil tends to dry out more quickly than in the garden. Although Panicum in the ground tolerates drought once well established, in a pot it will appreciate the substrate remaining moist during the hot season. In summer, potted Panicum should be watered about once or twice a week. Ensure the potting mix remains lightly moist but not waterlogged. During winter, space out watering.

Pruning

Wait until the start of spring to prune Panicum, to enjoy its foliage which remains decorative in winter. At the start of the growing season, cut the clump back to about ten centimetres from the soil. For more information, read our tutorial: “When and how to prune upright panic grass or Panicum?“.

Diseases

Panicum is not prone to diseases. It can occasionally be affected by rust, especially when the weather is warm and humid.

→ For more information in our advice sheet: Diseases and parasites of ornamental grasses.

Overwintering

Very hardy, tolerating temperatures down to -29°C, Panicum can stay outdoors over winter and does not need to be overwintered.

Repotting

You can repot your Panicum every two to three years, choosing each time a pot a little larger than the previous one. In the meantime, each year you can simply perform a top-dressing which involves renewing the surface potting soil.