Hibiscus needs two things to thrive: abundant sunshine and water. Make sure you choose a place where your sprinkler or hose will reach. The end of your downspout or a low spot in your landscape where rain tends to pool after a heavy downpour would be a perfect spot for a perennial hibiscus.
It’s best to plant this perennial before the heat of summer arrives. Start looking for one at your local garden center in early summer. Early fall is another good time to plant hardy hibiscus.
This perennial has a larger root system than most. It’s not so large that it will ruin your foundation, but it’s big enough that you will need to dig a large hole, so find a good shovel before you start. Dig the hole about twice as wide but just as deep as the container it is growing in. Add some water to the hole to moisten the soil before you set the plant in place. While you’re at it, water the plant in the pot one more time. Moist hole + moist plant = great results.
Don’t worry if you have clay soil–this plant has strong roots that will grow right through it. If your soil is mostly sandy and tends to dry out quickly, add several handfuls of humus, compost or aged manure when you backfill the hole. It will provide extra nutrients and water-holding capacity to the soil.
If the roots are densely circled around when you take the plant out of the pot, loosen them up a bit to break the “root memory”. This will encourage them to grow outward instead of continuing to grow in a circular pattern.
Set the plant in the hole, making sure that the top of the rootball is level with the top of the surrounding soil. Then backfill the hole with the soil you dug out and any amendments you may have added. Press it down with your hand firmly to eliminate any big air pockets around the roots.
Lastly, water the plant again to help the soil settle. Spread some mulch around the base of the plant, taking care to keep it from touching the plant’s stems. The mulch will help to retain soil moisture and protect the roots during winter.