Maximilian sunflowers (Helianthus maximiliani) are perennial plants that reach heights of 3 to 10 feet tall, depending upon growing conditions. They have hairy, medium-green stems and boast numerous vibrant yellow flowers from the end of summer into early fall. They grow best in full sun and flourish in practically any soil. Maximilian sunflowers are most often grown from seed, which require exposure to a period of cold temperatures before planting to ensure effective germination. Deer favor the foliage of the plants, while the numerous seeds produced in fall draw a host of wild birds to the garden.
Place the maximilian sunflower seeds inside a lidded container after gathering the seeds in fall. Put the container in the refrigerator and allow it to remain there until early spring. This step isn't necessary for seeds purchased at a garden center.
Cultivate the soil with a garden fork until it is loose 8 to 10 inches deep.
Remove all rocks and clumps of vegetation large enough to interfere with sowing the seeds.
Plant the maximilian sunflower seeds approximately 1/8 inch deep and water until the soil feels moderately moist.
Water only if a week passes without substantial soaking rainfall, as providing too much moisture may result in spindly stems that topple easily.
Add a 2- to 3-inch layer of mulch under the sunflowers when they are approximately 4 inches tall. Keep the mulch at least 3 to 4 inches from the stems.
Provide supplemental moisture when less than 1 inch of rain falls in a one week period throughout the growing season.
Place sturdy 3 to 4 foot stakes next to the stems of the plants if they begin to lean. Secure the plants to the stakes with garden twine.