by Linda Jenkinson
Choosing the right bulbs involves more than just selecting colors and cultivars. Timing, bulb size, and most importantly, bulb health are equally significant factors in designing your spring garden
Before purchasing any bulbs, know the differences in bulb types. Along with true bulbs, several types of flowers, sold as bulbs, grow from the underground stem growth of rhizomes, tubers, and corms.
- True bulbs are rounded, self-sufficient, underground storage organs. True bulbs are an incubator for a flower bud embryo already inside.
- Many perennial flowers grow from tubers, which are flat underground stems that store food and plant energy.
- Corms are thick underground stems that produce the new roots, leaves and flowers of their cultivars.
- Rhizomes are modified plant stems that grow horizontally under the surface of the soil. New growth emerges from several different points along each rhizome.
The first part in selecting healthy bulbs is knowing the bulb parts.
- The tunic of a bulb is the paper-like outside of the bulb that protects it from damage and keeps it from drying out.
- The scale leaves are under the tunic and hold all the nutrients needed to grow the cultivar.
- The first parts of the plant to push through the soil are the immature leaves, closely followed (or so we hope) by the flower bud and the stem.
- The roots of bulb cultivars grow from the basal plate, which lies at the bottom of each bulb.
- Healthy bulbs are firm, well rounded, and heavy for their size. Although bulbs come in a range of colors, some even with distinctive patterns, color should be uniform with no dark patches or light splotches. Discard any bulbs with weak spots or spongy area, which are signs of rot caused by disease or other damage.
A double-edged tip for selecting bulbs is “the bigger the bulb, the bigger the bloom”.
First, it helps you select cultivars and decide where to place them in your spring flower garden. For instance, crocus and anemone bulbs are tiny imps that beg a front row or outside border seat, while giant tulip or daffodil bulbs stand tall in back rows or keep watch over the center of your garden. Second, larger bulbs, within a particular cultivar, are generally more robust than smaller bulbs and produce stronger, healthier plants and blooms.
When choosing bulbs for a spring flower garden, consider both when they need to be planted as well as when you want them to appear. Most spring bulbs need to be planted in late summer or autumn. However, the reasons for the timing in planting spring bulbs usually aren’t relative to when the bulbs sprout in the spring. Rather, bulbs usually need to be planted when it is cool enough to keep them from sprouting, but warm enough to allow roots to become established before winter.
All spring bulbs need a cool weather rest period below 50°F in order to sprout successfully. If your climate is warm, you’ll need to provide them with a simulated winter before planting them.
• Tulips — 14 weeks • Hyacinths — 12 weeks • Snowdrops and scilla — 6 weeks • Crocus — 4 weeks
Although crocuses and windflowers are tiny, they are brave little imps and often the first heralds of spring. Generally, they’ll be followed by smaller tulip cultivars and narcissus. Still, even some of the larger daffodils and giant tulip hybrids may surprise you with an early appearance.
The best way to try to synchronize bulb growth with your garden plan is to check the growth patterns of each individual cultivar before purchasing and planting the bulbs.