Planting Bulbs, Corms, and Tubers

Not all plants start best from seed. Many, such as tulips, gladiolus, and dahlias, propagate best from underground storage organs (as discussed in Chapter 3). The methods for planting bulbs, corms, and tubers are similar to planting seed, except bulbs used for naturalizing or planted in grass. In these cases, don't prepare the soil in advance, instead use a handy bulb planter for forming holes.

For perennials, use a hand trowel to dig holes about three times deeper than the width of the bulb. This insulates the bulbs from extreme temperatures. Irises are one exception. Plant them with part of the rhizome above ground. Planting irises too deeply will kill them. Likewise, plant onions and garlic with the tops nearly exposed.

It is absolutely critical to place bulbs, corms, and other underground storage organs in the soil with the growing tip facing the sky. If you are not sure which end is the growing tip, check for roots. The growing tip is on the opposite end. Dahlias and other tuberous plants should have small growing shoots coming out of the tuber. Plant them so the tips of the shoots point up. Make sure you don't break or damage growing tips. Sprinkle a little bone meal in the hole before placing the bulb to help the roots develop. Place the bulb in the hole, fill with the soil removed from it, and press down gently.