A cemetery can be a tough place for any plant to live. The area is usually windswept and sunny with little overall maintenance given to the plants. Also, there are sometimes height restrictions put in place by the cemetery management. The ideal plant for a cemetery is small to medium in size, needs little or no pruning, grows in any soil, likes full sun, and is drought tolerant.
There are a number of zinnia varieties that will grow well in full sun. However, the tall cutting types grow so tall that a strong wind can blow them over and make them sprawl. The mounding types (up to 12 inches tall) known as the Profusion Series bloom all season, do not need deadheading, and are drought tolerant. Plant well-established plants and disturb the roots as little as possible when transplanting. Add plenty of water after transplanting so they can get settled. Zinnias grow in average soil. Zinnias are not frost tolerant.
Cosmos can be planted as seed on bare soil or as transplants. The red, orange, yellow, purple or white flower varieties grow up to 36 inches tall. They are drought tolerant and reseed freely. The seed needs to be covered with one quarter inch of soil when planted. Cosmos are not frost tolerant, but should come up from the previous season's seed the following spring after flowering.
Moss Rose is a ground-hugging plant that is very heat tolerant. Most varieties bloom in the morning sun and close in the afternoon although there are new varieties that have a longer bloom period. There are moss-rose varieties in every color but blue, with some double-flowering varieties. Plant in well-drained soil as soon as possible after the last-frost date so they can get established before the weather gets really hot. Moss rose reseeds and comes back the following year from the previous season's seed crop. However, it does not appear until late in the spring when the soil warms.
Globe amaranth or gomphrena is an unusual flower that looks like colorful, fuzzy balls. Varieties are available in mauve, purple, red and white. The plants are drought tolerant and come back dependably from seed every year. Globe amaranth grows up to 24 inches tall and wide.
There are several varieties of celosia, or cockscomb, with some more sun tolerant than others. The flowers are unusual red crests that feel like velvet. For cemetery planting, choose the crested variety that only grows up to 24 inches tall, rather than the plumed variety, which is not as drought tolerant. The blooms last for many weeks and produce lots of seeds for plants the following season.