As for types of plants, fall is the time to plant tulips, daffodils, crocus, hyacinth and grape hyacinth. Any of these would be a good choice for a wonderful spring landscape,
Hardy spring-flowering bulbous plants should be planted before the ground freezes in the fall. The usual time is from late September through early November. Early planting is essential to allow for good root development before the ground gets cold. If the plant can establish a healthy, vigorous root system before the ground freezes, it will be capable of rapid growth and development in the spring.
Regardless of whether planting just a few plants or a few hundred, it is extremely important that the bulbous plants are planted to the proper depths. Shallow planting increases the risk of frost damage to the plants. The general rule of thumb for proper planting depth is two to three times as deep as the height of the bulb. Depth is measured from the top of the bulb to the soil surface. In very loose, sandy soils, bulbs can be planted 2-3 inches deeper than normally recommended.
When planting large areas, it is easiest to excavate the entire area and lay the bulbs, corms, tubers or rhizomes in place and then backfill the area with the removed soil. The bed should be dug to a depth of at least 4 inches more than the recommended planting depth. Fill back in with 2 inches of the loose, removed soil. This creates a loosened bed for root penetration. To the next 2-inch layer, mix bonemeal or other fertilizers. Place the bulb on this layer and fill in with about half the soil. Apply water and allow the soil to settle. Add the remaining soil and water again. Once the water has drained away, mulch the bed with several inches of leaf mold, wood chips or some other organic mulch to prevent drying, freezing and thawing through the winter.
In areas where rodents can be a problem, encase the bulbs in ½-inch wire mesh. This will prevent rodents from digging and eating the plants and still allow the shoots to emerge from the ground.
Of the hardy, spring flowering bulbs, the genus iris deserves some special attention. There are some 300 species of iris organized into 27 subgenera, sections and series. Because they easily hybridize, there are hundreds of cultivars. Identification can become a gardener’s nightmare.
Iris will either have bulbs or rhizomes. Regardless of the type, most iris prefer full sun where they thrive. Well-drained but moist soils are important to floral development. If the rhizomes or bulbs get too dry during the summer, flower formation can be inhibited. Many irises are suited to use along streams, ponds or in bogs and marshes.
One of the biggest complaints heard about iris is that they don’t flower like they used to. Several environmental factors will influence flowering. Check for sunlight. Are the iris beds shaded?
When overcrowded, flowering will be reduced. The bulbs or rhizomes should be dug, divided and replanted, generally about every three years. Division should take place as soon as possible after flowering. If you miss the spring division season, wait until the fall when the nights are cooler than in July. Many people wait until August or September to divide iris.
A third factor that influences flowering is depth of planting. Iris rhizomes should not be set too deep The irises might not have been planted too deep originally, but over time, the rhizomes get covered by mulch and leaf litter and become buried. With regular division, this will not be a problem.
For more information, contact the UT-TSU Extension Office in Wilson County at 615-444-9584. Ruth Correll, UT Extension-TSU Cooperative Extension agent in Wilson County, may be reached at 615-444-9584 or firstname.lastname@example.org.