Broadleaf evergreen shrubs like andromeda are vulnerable in times of temperature extremes and more so if they are in containers. The container means that the roots of the plant are closer to the surface and less insulated than they would be in the ground. In winter, even plants that would be hardy in our area may find the additional cold they experience at the root too challenging. They will also warm more quickly in a period of mild winter temperature, so the whipsaw is greater. Summer heat will more directly affect the plant's roots.

Begin by choosing a plant that is well-sized for container growth and a container that allows adequate room for the root system of the plant with a margin of soil to insulate it. Remember that dark containers will heat up and expose your plant's roots to greater heat fluctuations in winter sun and heat extremes in the summer. 

Some high quality, dwarf cultivars include:

• Pieris japonica 'Bonfire' 
  Named for its young leaves which emerge deep red, becoming dark green. A smaller plant, up to about 3 feet tall, with dark red buds opening to white flowers with pink sepals. Early flowering and considered an ideal choice for a container.

• Pieris japonica 'Bonsai' 
  One of the most common miniature forms, under two feet tall, with leaves and flowers similarly tiny. Red buds open to cream-white flowers on pink stems.

• Pieris japonica 'Cavatine' 
  A dwarf cultivar, growing slowly up to about 30" tall and wide in a low mound. Leaves emerge red, turning dark green with late-blooming, dense chains of long-lasting white flowers. Known for cold-hardiness and late appearance of flowers.

• Pieris japonica 'Prelude'
  A dwarf plant up to 2 feet tall and spreading out to 3 feet wide. Long-lasting and late-blooming white flowers follow pink winter buds. New leaves are bronze to pink.

Care for evergreen shrubs in containers as you would those planted in the ground.  Water them well in the late fall so that they are in top condition when the temperature drops. Once the soil has frozen, mulch the top of the container, but do not allow the mulch to creep up the stem of the plant or clump under the leaves where it can harbor disease. Do not mulch deeply or the roots can be starved of air and water. Be mindful of water needs in the summer. The more protected the location of the container (protected by building structure, awning, other plants), the less likely you are to need extra barriers to protect container-planted shrubs in winter.

Read more about the care of Japanese andromeda (Pieris japonica) and where it grows best in our Guide.

Courtesy of NYBG Plant Information Service