Peace lilies (Spathiphyllum) are tender perennials, often displayed in pots in the home or office. Peace lilies can grow to heights of 1.8 to 2.4 m (6 to 8 feet), producing white flowers that grow on tall stems. Although peace lilies are commonly viewed as houseplants, if you live within the influence of the Gulf Stream, consider growing peace lilies outdoors. Care is minimal, especially if you have well-drained soil with the required pH.
Plant peace lilies in soil with a pH between 5.6 and 6.5. If you do not know the pH of your soil, purchase a soil testing kit from a plant nursery. If your soil does not meet the pH requirements, amend with lime or peat moss.
Check that the planting location receives plenty of daytime sunshine. Peace lilies require at least 6 hours of sunlight per day when grown outdoors. Peace lilies planted in shaded areas may fail to bloom or thrive.
Provide the outdoor growing peace lilies with plenty of water. Peace lilies require at least 2.5 cm (1 inch) of water per week, when growing outdoors. Keep the soil moist, but not wet, at all times. Do not let the soil dry out in between waterings. Press your fingers into the soil before each watering. If the soil feels moist at a 2.5 cm (1 inch) depth, do not add more water.
Spread a 7.5 cm (3 inch) layer of mulch around peace lilies grown outside. Mulching with sawdust, straw or bark chips will help increase water retention and reduce weeds, which will compete with the peace lily for water. Mulch will also protect the roots of the peace lily from the heat of the sun or unexpected drops in temperature.
Feed peace lilies growing outdoors an all-purpose fertiliser. Check the package labelling for frequency and allocation amounts. Peace lily plants grown outdoors appreciate fertilising in early spring and midsummer.
Add lime to the soil if the pH is below 5.6 or peat moss for soil above 6.5. Check the package label for allocation amounts. Pinch off dead leaves with your fingertips to encourage new growth.
Be careful when growing peace lilies outdoors in areas where children or pets play. Parts of the peace lily are toxic and can cause serious illness if eaten.