For gardeners in England there is no confusion. Growing conditions are relatively similar throughout the country and they match the needs of most spring-blooming bulbs. Whether it’s tulips and daffodils or anemones and fritillaria, British gardeners can usually expect these bulbs to act like perennials.
But here in the U.S., gardeners contend with a wide range of growing conditions. Soils, temperature extremes and precipitation amounts vary widely from state to state and even from county to county. This means bulbs that are perennial in my garden may not be perennial in yours.
As with other types of plants, when you can match a bulb to its preferred growing conditions, it will be more likely to settle in and call your garden home.
Keep in mind that most spring-blooming bulbs need to go through a winter chilling period in order to complete their growth cycle. Without adequate chilling, the flowers may not bloom or will not be fully formed. Winter temperatures should be 40°F or colder for at least 12 weeks.
If your winters are too warm, you’ll need to pre-chill the bulbs in a refrigerator and plant them into the garden in late winter. Pre-chilled bulbs should always be treated as annuals.
In their natural habitat, most spring-blooming bulbs grow at high altitudes in thin, rocky soils. This is why the bulbs should always be planted in well-drained soil that never gets soggy – especially during the winter months. Soggy soil causes bulbs to rot.
For spring bulbs, ideal spring weather is cool with consistent moisture. After the flowers have finished blooming and the foliage has died back, the bulbs will lie dormant until fall. During this summer resting period, the soil should stay warm and relatively dry.
Spring-Blooming Bulbs That Are Reliably Perennial
These bulbs are adaptable and unfussy. If you live in a cool climate and have suitable soil conditions, you can count on these bulbs to rebloom for at least 5 years. In most cases the bulbs will also multiply over time.
Alliums (some types including A. aflatunense and A. sphaerocephalon)
Scilla hyacinthoides (campanulata)
Leucojum (summer snowflake)
Scilla siberica (Siberian squill)
Galanthus elwesii (snowdrops)
Spring-Blooming Bulbs That Can Be Perennial
If the growing conditions are favorable, which means the bulbs are planted into well-drained soil that is never soggy, the following list of bulbs will usually bloom for several years before gradually declining. When growing conditions are ideal, some tulips (such as Darwin hybrids and Fosteriana) may rebloom for 5 years or more. In areas where the soil tends to be heavy and can stay wet for many months at a time, it's best to treat all of these bulbs as annuals.
Spring-Blooming Bulbs That Should Be Treated As Annuals
These bulbs always perform best the first spring after planting. In certain climates they may return and bloom for more than one year, but the growing conditions must be ideal. More typically, the plants bloom well the first year, but after that, they are unable to generate the energy required to produce a good crop of flowers.
You can learn more about spring-blooming bulbs here: How to Plan a Spring Bulb Garden, Planning and Selecting Fall-Planted Bulbs, and How To Care for Spring Flower Bulbs After They Bloom.