Tom Weaver is a horticulturist and takes care of the Dwarf Conifer Garden and Waterfall Garden. He has a bachelor's degree in environmental horticulture from the University of Minnesota, Twin Cities Campus. His favorite groups of plants are hardy cacti and anything with chartreuse foliage.
Bulbs are often thought of as a single season “wow,” beautiful in spring and gone by summer. This couldn’t be farther from the truth!
With a little planning, you can have beautiful displays of bulbs throughout the season. You can blend colors seamlessly for a year-long display, or you can mix things up seasonally to give yourself three or four new displays, one for each season! The ephemeral nature of most bulbs allows you to keep things fresh without constantly replanting.
This summer, we’ll be following the Graham Bulb Garden throughout the year to show how a palate of background perennial plants can be transformed into a stunning display of different colors and textures throughout the season.
So what’s blooming now in the Bulb Garden?
Winter aconite (Eranthis hyemalis) provides an important source of nectar and pollen for early pollinators. On any warm day, you can see hundreds of honeybees scurrying among the flowers.
Giant snowdrop (Galanthus elwesii) is often one of the first things we see blooming in the Bulb Garden. This year, the first flowers were seen on March 20, well-timed for the start of spring! Snowdrops are best planted near doors or paths where you can appreciate their delicate nature.
Dwarf reticulated irises (Iris reticulata) come in a wide variety of colors, but the one thing they all have in common is their rich color and striking presence in the garden.
Early scilla, or white squill (Scilla mischtschenkoana ‘Tubergeniana’), might not be the most readily available bulb, but its icy blue color and ease of growth make it a great choice for early spring color.
A number of tropical and semitropical bulbs can be used indoors to brighten up the winter months. Long-lasting blooms of amaryllis, Star-of-Bethlehem, and cyclamen are welcome additions to winter white.
Amaryllis (Hippeastrum) are probably the best-known bulb grown for forcing indoors in the winter months. In recent years, plant breeders have introduced dozens of new varieties ranging in size from small miniatures no bigger than 4 inches across to giant doubles that can reach 8 inches in size, with dozens of frilly petals. Most commonly found are the large, red cultivars such as ‘Red Lion’, but for a unique holiday plant, look for some of the less-common varieties such as ‘Amalfi’ (a smaller pink variety), ‘Zombie’ (a double-flowered salmon-and-white variety), or the unusual purple-and-green Hippeastrum papilio.
Amaryllis are easy to care for, requiring bright light and not very much water. They do not like to be overly moist, and perform best if allowed to dry slightly between waterings. Cooler rooms prolong flowering, so make sure not to place it next to a heating vent. After they are done blooming, plants can be kept alive until summer, when they’re best placed outdoors to receive ample sunshine. When you return them indoors in the fall, stop watering, and allow the foliage to dry out and turn yellow. The plants will remain dormant for anywhere from one to three months. During this time, they require very little water (water approximately once a month). When you see new growth starting again, move the bulbs to a sunny location, and start the process all over again. As they age, amaryllis bulbs will get larger and larger, sometimes splitting into multiple bulbs. When this happens, they can be divided and potted up separately.
Another beautiful—but less common—plant that provides winter cheer is Ornithogalum ‘Bethlehem’, or Star-Of-Bethlehem. These bulbs produce a 1- to 1½-foot-tall spike loaded with clean, white, star-shaped blooms. They grow best in a bright, cool location—the same type of environment an amaryllis prefers. Special care must be taken to not over water these, as they dislike having wet feet. In addition to the classic white flowers, a newer species, Ornithogalum dubium, has become available recently, with flowers ranging from buttery yellow to neon orange.
Florists’ cyclamen, Cyclamen persicum cultivars, are related to hardy cyclamen (Cyclamen coum and C. hederifolium), but are not hardy in northern climates. They’re also generally much larger plants, suitable for using as a living centerpiece, or tucked into a gift basket for the holidays. Plants range in size from minis that are 3-6 inches tall, up to full-sized plants that can be nearly a foot tall when in bloom. The flowers come in many shades of reds, pinks, and purples, and in white. There are many beautiful bicolors and even some plants with exotic, frilly petals. In addition to beautiful flowers, cyclamen also feature some of the most intricately pattered leaves of any houseplant. You can get plants that are all silver, silver with green veins, green with silver veins, and many other unique patterns.
Cyclamen prefer to be grown in a cool room and kept slightly moist. They never want to be sitting in a tray of water, and they never want to be completely dry. If your plant does start to wilt, give it a drink of water, and it will perk back up in just a few hours. Like the two previously mentioned bulbs, your cyclamen probably will go dormant in the summer. If that’s the case, just cut back on the watering until new growth starts again in the fall.
When picking a cyclamen, try to pick one with as many buds as possible. Each plant is capable of producing dozens, sometimes nearly 100, blooms that open slowly over the course of the entire season, giving you several months of blooms. Because the buds are produced all at once, it is important to pick one with as many buds as possible; this way, you know that you’re going to maximize your bloom time.
All three of these plants are currently on display in Wonderland Express and the Semitropical Greenhouse.
Just when the hostas, lilies, and other garden perennials are going to bed for the season, these bulbs are waking up.
Arum first emerge in the late fall. The broad, arrow-shaped leaves of Arum italicum are highly ornamental and sturdy—quickly perking up after hard freezes, providing a welcome spot of green in the winter garden. Throughout the winter, they remain green and full, providing a welcome burst of green in the winter garden. In the late spring, they send up creamy white flowers that resemble calla lilies (Zantedeschia sp).
Soon after flowering, the leaves die for the season, revealing showy, fruiting stalks of bright red, highly ornamental berries. While these berries are quite attractive, do be aware that they’re poisonous and should be planted where they won’t tempt any children or pets to eat them. If located in an ideal site, they will reseed and form a ground cover. There are dozens of varieties, each with its own unique leaf patterns.
There are two primary types of cyclamen that are hardy in Chicagoland. These are the fall-blooming Cyclamen hederifolium and spring-blooming Cyclamen coum. The fall-blooming Cyclamen hederifolium have ivy-shaped leaves with stunning silver patterns and small, windswept-looking flowers. Cyclamen coum blooms in the late winter or early spring, and has heart-shaped leaves with silver patterns.
Both plants grow their leaves in the fall and carry them through the winter before going dormant in the spring. Their flowers range in color from pinks and lavenders to white. Cyclamen prefer a shady spot that doesn’t stay wet; otherwise the bulb will rot.
A great place to plant cyclamen is under deciduous trees, where the leaf canopy will protect the dormant tubers from excess rain. If sited properly, they will reseed and form a ground cover.
Among the latest-blooming bulbs are the often overlooked Allium thunbergii ‘Ozawa’ and A. thunbergii ‘Ozawa Alba’. These relatives of onions form grassy clumps that look green and fresh all summer long and suddenly burst forth with small clusters of flowers resembling pink-and-purple lollipops in late October, often continuing until mid-November. (As of November 17, these were still going strong in the Farwell Landscape Garden, even after hard rain, several hard freezes, and a light snowfall!) Allium thunbergii prefers to be located in a sunny, well-drained location, where it will continue to grow and thrive for many years. These are great plants for a sunny rock garden, where they provide a welcome shot of color at the end of the season.
Selections of Fritillaria imperialis and Fritillaria meleagris are available at our Fall Bulb Festival this weekend; many additional varieties can be found in specialty catalogs.
Fritillaria are some of the most unique spring-flowering bulbs you can grow. Available in nearly every color (except blue), many have interesting patterns on the petals.
Combine this with a worldwide distribution and you’ll find that there is a fritillary for nearly any spot in any garden.
Fritillaries range from Fritillaria meleagris, on the small end at approximately 6-8 inches tall, to Fritillaria persica, which grow to 5 feet tall and are covered in nearly black, bell-shaped flowers. Some of the most commonly available and popular varieties include Fritillaria imperialis, which comes in orange, red, yellow, and variegated forms; Fritilaria meleagris, commonly called the snake’s-head or guinea hen flower because of its unique checkered petals; Fritilliaria uva-vulpis, which has charming yellow and maroon flowers; and the above-mentioned beauty, Fritillaria persica.
Perhaps the best fritillary for the home gardener is Fritillaria meleagris. These undemanding plants will readily naturalize when happy and come in shades of purple and white. Their grassy foliage blends in well with other spring flowering bulbs and the often dark flowers stand out well against the blues and yellows of other spring flowering plants. Their biggest demand is that they never dry out completely in the summer, which makes them perfect for mixed borders that receive supplemental water in the summer. They do best in filtered shade, which helps prevent too much drying out.
Another excellent fritillary for home gardeners is Fritillaria imperialis. This regal plant comes in several colors and has a bold presence. In late spring, the lily-like plants are crowned with a ring of vibrant orange, red, or yellow bells that light up the garden. They can have a somewhat pungent smell, so they’re best appreciated at the back of the flower border. (Although the fact has not been proved, this smell is said to repel rodents.) There are several varieties commercially available, including a variegated form.
When planting imperial fritillaries, care should be taken to plant the bulbs on their sides. Large fritillary bulbs tend to have a hole in the center which can retain water and rot the bulb. This is easily avoided by planting them on their side so that water can’t build up. Another way to help avoid rot is to make sure they’re planted in a well-drained, sunny location.
Consider adding fritillaries to your garden this fall, and welcome spring with a glorious display of color!
When most people think of bulbs, they think of spring-flowering plants such as tulips and Narcissus, or maybe summer ones such as Allium or lilies. One often-forgotten season is fall, even though fall is prime time for one of the most carefree and surprising bulbs of all, Colchicum.
Commonly known as autumn crocus or meadow saffron (although it is important to note that they are neither saffron nor a crocus and are poisonous if ingested), these lovely ephemerals are jewels in the fall garden.
Although they’re commonly referred to as a bulb, Colchicum are not a true bulb, but are corms, much like Gladiolus and Freesia. Colchicum have an unusual habit of growing their foliage in the spring (just like most plants), but then instead of flowering, they go dormant for several months. Then, seemingly out of nowhere, they send up dozens of purple, pink, white, or checkerboard flowers just as the rest of the garden is getting ready for fall.
Colchicum prefer a location with full sun until midspring and grow best in a location with well-drained soil that does not stay wet during the summer dormant period. This makes them ideal for planting under trees, where other plants might not compete as well with the roots. The bulbs should always be planted two to three times deeper than the bulb is tall to help ensure a long life.
To appreciate these intricate flowers, plant Colchicum in large groups near the front of a border. Because the foliage remains green until early summer, it is best to either plant them in an area with a groundcover, or to choose a low-growing annual to plant over them once the foliage has gone dormant for the season. This not only hides the bare ground, but also provides some support to help keep the flowers upright.
Look for Colchicum at the Chicago Botanic Garden beginning in mid-September and continuing through October. The Bulb and Home Landscape Gardens have the best displays of this fall beauty.