How To Plant, Fertilize, Prune & Water Panicum Switch Grass Plants

Posted by Brent Wilson on 10/11/2016 to Fertilizing & Watering Tips

When planted right and in the right spot, the North American native switch grasses, scientifically known as Panicum, are exceptionally easy to grow in the ground or in containers.

Here's a breakdown of what you need to know...

Cultural Preferences

Soil

Switch Grass is a North American native grass that is very easy to grow. They tolerate a wide range of soils, even clay and sandy soils and dry soils, but prefer the soil to be moist. They tend to like an average soil that isn't too rich in organic matter, which can cause plants to flop. So there's no need to add compost or humus to the native soil when planting.

How To Test Soil Drainage

If you are uncertain about soil drainage in the area you intend to plant your switch grass, it's well worth taking the time to test the drainage before planting. To test soil drainage, dig a hole 12" wide by 12" deep in the planting area. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and the need to add moisture retaining soil amendments. A slower rate indicates poor draining soil. Switch grasses prefer a consistently moist soil, however, constantly wet soil or standing water can be problematic.

Soil pH

Switch grasses grow best in a moderately acid to moderately alkaline soil ranging from 6.0 to 8.0 on the pH scale. Most average garden soils range between a pH between 6.0 to 7.0.

Testing Soil pH

Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline.

If you're unsure about the pH of your soil, or suspect your soil is not suitable for growing switch grass, it's a good idea to test the pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.

Learn More: What is Soil pH and How To Adjust It?

Light Needs

Switch grasses grow best in full sun but will tolerate some light shade. Too much shade and plants will become floppy. Very easy to maintain, all you have to do is cut the clumps back to the ground in late winter, before new growth begins to emerge. Cut back clumps to the ground in late winter to early spring.

Step-By-Step Planting Instructions

Scroll down for container planting instructions

Step 1

Start by digging your planting hole two to three times as wide and as deep or not much deeper than the root ball of your plant. The wider the hole the better. Place native soil removed from planting hole around the perimeter of the hole, in a wheel barrow, or on a tarp.

Step 2

Depending on the type and porosity of the soil in the planting area you might need to amend the native soil. When planting in dense clay it is beneficial to thoroughly mix in some bagged top soil at a 25% percent ratio to the native soil removed from the planting hole. When planting in very sandy, quick-draining soil mix some top soil, peat moss and/or compost at a 50% ratio to the native soil for moisture retention. When planting in average, well-drained soil there is no need for adding a soil amendment.

Step 3

Tip: Water the root ball deeply before removing the plant from its container.

To remove your grass plant from the container it was growing in, firmly grasp the base of the plant and try to gently lift and remove it from its container. If the root ball is stuck in the pot place the plant on it's side and gently tap on the side of the container to loosen the root ball or cut the container away. After having removed the plant from the container, loosen some feeder roots around the surface of the root ball. If root bound, you can gently spray the sides and bottom surfaces of the root ball with a stream of water from a garden hose. This will help to wash away some soil from the exterior of the root ball making it easier to loosen roots.

Step 4

Set your switch grass in the planting hole so that the top edge of the root ball is at or slightly above ground level to allow for settling. It may be necessary to place some of your backfill soil mixture in the bottom of the hole to achieve proper planting height.

Note: If there is standing water constantly in the planting area you can create a mound of soil completely above ground level to plant in.

Step 5

After setting your switch grass in the planting hole, use one hand to hold the plant straight while using your other hand to begin backfilling the soil mixture around the root ball, tamping as you go to remove air pockets. When you have filled the hole to the halfway point you can soak the soil. Then continue backfilling to the top edge of the root ball.

Step 6 (Optional)

If you are planting your switch grass in a location far away from a water source you can use remaining soil mixture to build a water retaining berm (water catch basin/doughnut) around the outside perimeter of the planting hole. This basin will help to collect water from rainfall and irrigation often reducing the need for hand-watering. The berm can be removed after a growing season.

Step 7

Next, deeply water the planting area, including the root ball, to a depth equal to the height of the root ball.

Step 8

Apply a 1 to 2" layer of cured, shredded wood mulch or bark or pine straw, around your newly planted switch grass. Avoid the use of freshly chipped or shredded wood for mulch until it has cured in a pile for at least 6 months, a year is better.

Container Planting Instructions

Switch grasses growing in pots appreciate a consistently moist but well-drained soil. Therefore, when planting in a container or pot, we recommend using a high quality potting soil or professional potting mix, or a 50/50 combination thereof, and a container with a drainage hole(s).

Choose a container that is large enough to allow for 2 to 3 years of growth before shifting up to a larger size container. This might mean your planting pot would be 8 inches or more in width than the root ball of your plant.

Container color will matter as well. Not only will you want to pick a color of container that goes well with the foliage color and texture of your switch grass, you'll also want to pick a container that matches the style of your home or other structures and other plants in the surrounding environment.

Many nursery & garden centers offer a wide variety of containers to choose from. Before heading out to buy a container take pictures of your home and the surrounding environment. Doing so will help you to choose just the right color and style.

Container Planting Instructions

Step 1

Before filling your container with the soil mix, we recommend lining the bottom with shade cloth or a porous landscape fabric. This will keep the drain holes from becoming stopped up with soil.

Step 2

Step 3

Pour a small amount of your soil mixture in the bottom of the container. Set the plant in the container and make necessary adjustments by adding or removing some soil so that the top edge of the root ball will sit approximately 1" below the rim of the container.

Step 4

Backfill with your potting soil around root ball, tamping as you go, until the level of potting soil is even with the top edge of root ball.

Step 5

Water thoroughly until water starts to drain from the holes in the bottom of the container. Add more potting mix if settling occurs during watering.

Step 6 (Optional)

Apply a 1/2" layer of wood chips or sphagnum moss to soil surface to help conserve moisture. Stone mulch can also be used. You might also consider planting spreading seasonal flowers or perennial groundcover plants around your switch grass as a soil cover.

Switch Grass Care Tips

Feeding - Watering - Pruning

Switch grasses are exceptionally easy to care for. Below are some helpful care tips that will have you growing them like the pros.

How To Fertilize Switch Grasses

Switch grasses do not require fertilization. Too much fertilizer, especially those high in Notrogen, can cause excessive foliage growth resulting in floppy plants. If your switch grass are not growing well and look like they could use a boost, you can feed them annually in spring with a mild, slow-release organic plant food. Before applying fertilizer, always carefully read and follow instructions on the product label.

How To Water Switch Grasses

At Planting Time

Immediately after planting deep soak the soil in the planting area to a depth equal to the height of the plants root ball.

During the First Growing Season

In average garden soil you should not have to water your newly planted switch grasses every day. In the absence of sufficient rainfall, water only as needed to keep the root ball and surrounding soil consistently moist. Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day.

Note: Ornamental grasses planted during the winter dormant season, when plants are not actively growing and evaporation is much slower, will require less water.

Thereafter

When established switch grasses will tolerate short periods of dry weather. That said, they prefer a consistently moist soil and therefore will appreciate an occasional good deep soaking during prolonged periods of drought.

Note: When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night, which can lead to the onset of fungus and other foliar diseases. During the first few weeks after planting, check soil moisture often and adjust irrigation time if necessary to keep the soil moist, not wet.

How To Prune Switch Grass Plants

When to Prune

I usually leave the foliage of my switch grasses stand throughout the winter for visual interest. That being said, substantial clumps tend to flop or totally collapse when subjected to heavy winter snows. If you live in an area that is known to receive heavy snow you can cut foliage halfway back before snow arrives. Otherwise, wait to prune until late winter or very early spring, before or just when you see new growth begin to emerge.

If you wait too long, and new foliage has already emerged, go ahead and trim the old foliage back. It's better to do that than to look at old straw-color foliage mixed with fresh green growth throughout the season.

How To Prune

Before pruning your ornamental grass it can make the job a lot easier if you first tie the grass up with a string or rope. Simply gather up all the dead blades and tie a string around them. Then proceed with pruning.

Use hedge trimmers or clippers or a sharp pair of bypass hand pruners to trim foliage to just above the ground. I usually prune back to about 3 to 6 inches above ground. That's about it!

How To Prune Ornamental Grass Plants >

How To Measure for Total Square Feet >

How Many Plants to Fill a Planting Area >

Plant Long & Prosper!™

Questions? Contact Us!