Spring Bulb Aftercare: Ensuring Healthy Bulbs Post-Bloom
After our spring bulbs herald spring, a few care techniques promote perennialization for more seasons of sweeping color. Gardening expert Katherine Rowe explores how to care for bulbs as they prepare for dormancy post-bloom.
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From the earliest blooms of snowdrops and crocus to the riotous color of daffodils and tulips, there’s nothing quite like spring flowering bulbs to cheer on the season after a long winter. Their effortless beauty, low maintenance requirements, and easy planting make them accessible to tuck into garden pockets and containers and to create large, sweeping drifts.
To continue the infusion of color next spring and beyond, proper post-bloom aftercare promotes the best perennialization. The goal is to maximize energy storage in the bulb for summer dormancy and overwintering for reemergence the following spring. With a few techniques to promote strong bulbs after flowering, the ability to naturalize and perennialize improves for long seasons of enjoyment.
Select Perennial Species
With complimentary blooms, bulb combinations are nearly endless and welcome warming conditions from the earliest bloomers in late winter to the late comers that last into early summer. Spring-flowering bulbs are carefree and easy to grow, often with similar cultural requirements for pairing and combining. While each genus has certain cultural conditions for the best growth, our spring favorites have overlapping care needs after flowering.
The first step in planting is to choose those hardy to your growing zone. Many bulbous species are cold-hardy, and in USDA zones 3-8, they bloom for successive seasons where they perennialize and spread to form small colonies. With the exception of tulips, which perform best the first year, many are long-lived (snowdrops, daffodils, crocus) as they develop offsets that keep the population going in ideal situations.
Spring flowering bulbs usually grow best in areas with cool, moist winters and warm, dry summers. While there are differences in the longevity and speed of growth among types, post-bloom treatment is important across species.
Favorite species include:
- Amaryllis
- Crocus
- Daffodils
- Glory of the Snow
- Hyacinth
- Ornamental Allium
- Paperwhites
- Snowdrops
- Spanish Bluebells
- Tulips
- Windflower
- Winter Aconite
The Right Site and Conditions
After choosing perennial species, the best foundation for their establishment is the proper planting location. Most grow best in full sun to partial shade. They enjoy the benefits of winter sun through a deciduous tree canopy, followed by cooling shade in summer after leaves emerge. Sunlight during active growth promotes the best flowering and vigor.
Well-drained soils are essential to health, especially during the dormancy period. Prolonged periods of soggy conditions in the summer or winter make them susceptible to bulb and root rot. Consistently moist soils with good drainage are best during the growing season, while drier conditions in the warm season mimic their native range.
Spring-flowering bulbs do best with fall planting. Many require a necessary chill period, or vernalization, that naturally occurs with overwintering. Plant them in fall or as late as winter in workable soils.
Gauge Fertilizing in Spring
Healthy, organically rich soils usually need no additional fertilizer. For perennial bulbs, especially short-lived selections like tulips, and those lean soils, an application in spring helps them uptake and store energy for dormancy.
Apply a low-grade organic fertilizer (like a 5-10-5) after flowering. Avoid getting fertilizer on the foliage, and give a cleansing rinse after applying. Keep an eye out for weeds that become competitors for nutrients during this time, and hand-weeding benefits the flowers.
You can also opt for a fresh layer of compost post-flowering to support soils and build health in lieu of fertilizer.
Cut Off Spent Blooms
Part of spring-flowering bulb aftercare is deadheading. Removing spent blooms, when feasible, extends the vigor of plants, especially for short-lived selections like tulips that you hope to carry over. In large swaths, this isn’t necessarily achievable, and they’ll survive without deadheading.
Deadheading prevents the plant from producing seeds. The energy that would go into seed production goes instead into food storage for the bulb. If flowers are wilting and dropping petals, it’s time to cut off the flower head. If the stem is green and strong, leave it in place to continue photosynthesizing. Remove only the flower parts and stalk—the foliage needs to stay in place.
Leave the Leaves
Once the bulb flowers (reproduces), the foliage begins to decline as the bulb prepares to enter dormancy. Throughout the growing season, it stores energy and nutrition reserves for the following year. While the strappy leaves aren’t so attractive post-bloom, leaving them in place is an essential part of spring-flowering bulb aftercare. They allow growth processes to continue until dormancy. The foliage continues to absorb sunlight and nutrients for the bulb, and removing leaves too early means halting bulb development.
Remove leaves (if desired) when they turn yellow and brown. They’ll separate easily from the top of the bulb when no longer working to support growth. Leaves usually fade within six to eight weeks of flowering. With diminutive species like crocus, snow in summer, and winter aconite, you may not notice the fading foliage as the season progresses.
To conceal yellowing foliage, plant among other perennials that emerge in spring and cover the declining leaves. Hosta, astilbe, geranium, epimedium, coral bells, and ferns are a few that bring fresh growth and tolerate dryer conditions during the warm season once established (the same conditions dormant bulbs need). Surrounding plantings also suppress weeds that crop up in warming temperatures.
Stop Irrigating
After blooming, reduce irrigation (if you’re adding supplemental water). Stop altogether as leaves begin to yellow. When the plants enter dormancy, they’re no longer actively uptaking moisture to support upper growth.
It’s best to reduce watering after blooming when the foliage fades. Stop watering a few weeks after flowering. Bulbs rely on regular moisture during the growing season, but upon dormancy, they don’t need excess water. After blooming, reduce irrigation (if any), stopping completely as leaves begin to yellow. Oversaturation can lead to bulb and root rot.
Dig, Divide, Transplant
Left undisturbed, perennial bulbs form compact colonies over time. They don’t often need dividing and can go for years without interference. If they show less blooming from crowding or need to move to a sunnier location, or if you’re ready to expand them to other areas of the garden, it works to do so right after flowering. Dig and move them while the leaves are still green, before dormancy. You can also move and divide bulbs in the fall during the ideal planting time.
To divide and transplant, dig about six inches away from the bulb cluster. Stick the shovel, spade, or fork deep enough to lift the bulbs with a push. Separate them into singles or smaller clusters for transplanting. Mother bulbs may have small baby bulbets attached. If they’re ready to grow independently, they’ll separate easily with a tug. If not, leave them attached to continue developing and plant the pair together.
Add Mulch or Compost
In cold climates, spring-flowering bulb aftercare includes a mulch or compost cover in the winter. In the summer, it provides a cooling effect by regulating soil temperatures. During early season warm spells, it keeps leaves from popping up too early. In late winter and early spring, pull back the mulch layer from the crown as new growth emerges in spring, but keep a layer atop the roots.
At planting, add a layer of compost and mulch to help regulate soil temperatures, retain moisture, and suppress weeds.
Lifting and Storing for Summer
While perennial bulbs spend the year in place, some gardeners dig them up – particularly tulips—to preserve them for planting the following fall. Digging or “lifting” bulbs for the summer spares them extreme temperatures and overly wet conditions, though it doesn’t guarantee reblooming. If your climate is hot and wet or your soils are poor-draining, lifting is a helpful technique if you don’t want to risk leaving them in place. Lifting is also useful in warm climates that lack the necessary chill time to promote flowering.
The best time to dig bulbs for summer storage is after the foliage fades. Dig bulbs and remove any remaining foliage. Gently shake off any excess soil and inspect them for soft spots and moldy areas. Toss any with signs of these, saving only solid, firm bulbs – the bigger, the better for future flowering. Lay bulbs in a ventilated area away from direct sunlight to dry for one to three weeks. The outer skins will be papery when fully dry.
After drying, store the bulbs in a cool, shaded, and ventilated space like a garage or basement. In areas with warm winters, provide a refrigerated cooling period prior to planting for those that require a chill time.
Tuck the dry bulbs in for the season in a paper or mesh bag (like a citrus produce bag) or an open crate. Keep them in the same dry, sheltered area, and inspect them periodically. Hang bagged bulbs to increase air circulation. Ideal storage temperatures are in the 60s (~16°F).
Bulbs in Containers
Spring-flowering bulbs grow beautifully in containers. After blooming, treat them the same way you would in-ground plantings by stopping watering and transplanting them into the garden to perennialize or lifting them for summer storage.
