How to grow Panicum

Panicum virgatum is the botanical name of a variety of grasses more commonly referred to as Switch Grass. They are medium to tall height, mounding-forming plants with frothy looking green, blue or golden leaves, often with colourful accents to the tips. Thin, upright stems of small flower spikes in early to mid-autumn create the impression of a haze of flowers. Particularly attractive with light shining through them early or late in the day, especially those whose foliage changes colour later in autumn.

Originating from North America, where they thrive and spread readily creating large swathes of grassland, Panicum virgatum are an attractive and easy-going way to edge a border or pathway, and they mix well with other perennials as well as other groups of ornamental grasses offering ‘on trend’ prairie style impact. We supply several of these grasses, with two AGM holders (‘Heavy Metal’ and ‘Northwind’) amongst them.

Most are deciduous, yet still useful over winter when spent foliage is kissed with frost for magical impact at a sparse time of year. They also add animated interest as both the leaves and the flower stems will gently sway in the breeze offering transfixing beauty. All like a spot in full sun with free-draining, soil of any kind except heavy clay.

Zantedeschia is a genus of flowering plants from the family Araceae and is native to southern Africa. With a rich history dating back to the Ancient Romans, these deciduous or semi-evergreen perennials have been used as a symbol of celebration. Zantedeschia was Named after Professor Giovanni Zantedeschia, an Italian botanist.

There are two main forms of Zantedeschia: hardy and tender. Hardy forms of the plant can be grown outdoors, enjoy moist soil and full sun or partially shaded conditions - these are known as Arum lilies. Tender forms of Zantedeschia prefer being grown in containers or pots and should be brought inside over the winter - these are known as Calla lilies.

With tuberous flora in all colours from whites, yellows and oranges to deep reds and purples, Zantedeschias are not to be overlooked in any garden, as long as they have sufficient sunlight to grow in.

Ready to learn more about growing Zantedeschia? Read on for all there is to know...

Key Information

Soil pH

Position

Hardiness

Where & when to plant Panicum

Position - Full sun and a south, east or west facing aspect

Soil - Happy in well-drained soil of any kind

Flowering Period - Autumn

Hardiness - A hardy (H5), clump-forming grass tolerant of temperatures down to -10 to -15°C.

Ideal for gardens where temperatures are unlikely to drop below -10°C – which encompasses the majority of the UK. It is important to plant Panicum virgatum at a time when they are most likely to settle in well – this is late spring and early summer. The next thing to bear in mind is that Panicum virgatum like an open, sunny position which benefits from light, moist yet freely draining soil which is moderately fertile. As said, plants will also thrive in containers; just make sure you choose one of a suitable size for your plant! Also ensure your container has drainage holes in the bottom so your Panicum virgatum does not become waterlogged.

How to plant Panicum

For planting in containers, first choose an appropriately sized pot and ensure that you do not swamp your plant by choosing too large a container.

If you are using a large or heavy pot, it can be a good idea to fill and plant it in situ to save yourself the trouble of moving once full.

Use a good quality free draining compost, and, if not already present in the compost (check the description on the bag) some suitable slow-release fertiliser granules.

Start by partially filling the pot with compost; enough so that when placed on it the upper surface of the root ball is about 3cm lower than the top of the pot.

Infill all the space surrounding the root ball with compost, firming down with your fingers then adding a little more so the plant is held tight.

Pick up the container and lightly tap on the potting bench or ground a few times to help further settle the compost around the plant.

Water well to both settle the soil and give the plant a good drink.

A mulch with horticultural grit will look attractive and help to prevent a ‘cap’ or crust forming on the top of the compost (something container plants can suffer due to the artificial nature of their watering).

For planting in the garden, ensure you choose a spot with appropriate levels of sun

Dig the soil area removing any large stones and weeds and breaking up any lumps. Mix some organic matter into the soil. If your soil is heavy clay, now is also the time to add a generous helping of horticultural grit to adjust the drainage accordingly.

Rake level and firm with your heels. Rake level again.

Water plants well and allow to drain before planting. A good tip is to dig a hole twice the size of the root-ball.

Place the plant in the hole, ensuring the top of the root ball sits level with the surface of the soil. Too low and the plant may rot, too high and the roots can dry out.

Backfill with soil and firm in gently with your foot.

Soak well with water to settle the surrounding ground.

What to plant with Panicum

These grasses are beautiful in their own right and ideal for locating anywhere in the garden which offers the necessary protection and allows you to make the most of the beautiful foliage and flowers. They combine well with other grasses and perfectly compliment hot colours in prairie garden as well as cooler colours in containers or a sunny border.

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How to care for Panicum

Pruning

Deciduous grasses need very different care to evergreen ones. Both should be left in place over winter with the wind damaged old growth of deciduous varieties best cut off close to the ground in early spring before the new growth starts to shoot. Evergreen varieties can also be neatened up in spring by combing through the fronds with your fingers, leaving only the healthy growth behind.

Watering

Water your new plant regularly for at least the first two years. Once established, it should cope well without extra watering, except in particularly hot, dry spells. Bear in mind these plants are drought tolerant once they have established a good root structure and dislike being waterlogged.

Feeding

Once established in the ground a single application of fertiliser each spring should be sufficient. Plants grown in containers need a little more attention as they do not have such ready access to nutrients – feed with a general purpose liquid fertiliser through the growing season which is March to October.

Pests and Diseases

Panicum virgatum generally suffer from few problems if planted in an appropriate position. However, they may occasionally have difficulties with:

Rust: a fungal disease which appears as rusty-coloured patches on the leaves. It can be largely avoided by dividing overcrowded clumps and allowing better air circulation around plants.

Lack of flowers: usually caused by insufficient light. Resolve by reducing the shade from neighbouring shrubs or move the grass to a more open position. Overfeeding can also promote leaves at the expense of flowers

Rabbits and voles will sometimes eat these grasses though your plant should recover if not eaten in its entirety.

How to propagate Panicum

This can be done by sowing from seed or by division.

Sowing from seed:

Cut well-developed flowerheads just before the seeds are fully ripe.
Put the whole seedhead in a large paper bag, bring indoors and allow the seeds to ripen naturally.
Sow the seeds in autumn at a temperature of 10°C or store them cool and dry over winter and sow in spring.

Propagating by division:

The best time for this task is early spring just as plants are beginning to resprout after a dormant period during colder weather.
Simply dig up and lift a large clump and divide it into several smaller sections.
Replant these smaller sections either into pots for transplanting once established or directly into open ground.
Water well and ensure soil remains moist whilst these divisions establish themselves

*Many plants carry Plant Breeders Rights and cannot be propagated for commercial purposes.

Common Panicum questions

Does Panicum virgatum come back every year?
If your plant is hardy then, yes, it will return each year – dying back over autumn and reviving each spring. The varieties we sell are perennials. However, if you buy a tender plant or one which is described as an annual it may not return the following year.

How long does it take to grow Panicum virgatum?
You can expect your Panicum virgatum to mature over 2-5 years after which it may begin to become overcrowded – at this point your plant is easily reinvigorated by dividing in spring and offering new plants some slow release fertiliser.