Spring Bulbs that Naturalize

Well it’s bulb planting season once again and while most of us are focussed on showy Tulip or Daffodil varieties, there are also many lesser known types that can be naturalized and enjoyed in your garden for years to come. These spring flowering bulbs come in many shapes and sizes – from the diminutive Snowdrop to the giant Flowering Onion – so there are a myriad of colours, heights and flower forms to choose from. When properly planted and cared for, these bulbs act as perennials; often growing foliage through late winter, blooming in spring and going dormant by the heat of summer.

Location & Planting

While not particularly fussy, all naturalizing bulbs require adequate soil drainage or they will simply rot during our wet winters. If this is a problem for you then consider planting them in containers which can be placed out in the garden while they in their prime and moved to a less visible site as they dieback or are in their dormant state. Spring sunshine is another necessity, as many of them like Crocus don’t even open their flowers until exposed to light. Bulbs should be planted in either small rounds or drifts, so that when they emerge in spring they look like small bouquets or undulating waves of colour. This means a minimal cluster of 5-10 bulbs for a round and 15-20 for a small drift. Avoid solitary plantings as they look rather pitiful all by themselves and it takes at least 5-8 years for a single bulb to multiply into a presentable display. If you have sandy ground then consider adding some blended topsoil to the planting, but avoid straight manures as these are too moisture retentive and can cause rotting. Planting depth is usually indicated on the packaging, but as general rule a depth three times the height of the bulb works well. Bonemeal at the bottom of the planting hole is a necessity when naturalizing bulbs, just be careful not to get any on the soil surface where it will attract Raccoons. If Grey Squirrels are digging up your newly planted bulbs then consider sprinkling a rodent repellent on the soil surface or pinning a small square of chicken wire over the planting until the bulbs have rooted in (usually a few months later). While naturalizing bulbs in lawns can be done in colder regions, here on the coast our grass often grows so quickly in late winter that it would literally smother the flower display, so it is not recommended here. Well, now that we know where the bulbs should go and how to plant them, let’s move on the flowers themselves.

Flowering Onions

Allium moly
Allium moly

Alliums are a largely overlooked family of flowering bulbs mostly because they bloom after the tulips and daffodils, from late spring into early summer. This delayed display has also led to some confusion as to when to plant them, but since they are available now with your regular bulbs, they should be planted in the fall along with them. While most of us are fixated on the larger-flowered types – such as Allium giganteum, ‘Mount Everest’ and A. schubertii with its fireworks-like blooms – you also have to remember that the base foliage turns brown just as they come into flower, so stage them accordingly. One of my favourites is ‘Purple Sensation’ with its abundant violet blooms of about 4” across, which make great cut flowers or dried heads for arrangements. Another worthy flowering onion is the shorter (6”) Allium moly with its bright chrome yellow blooms over foliage that is much less prone to dying back during flowering.

Allium schubertii, Allium 'Mount Everest', Allium 'Purple Sensation',

Minor Bulbs

Glory-of-the-Snow or Chionodoxa luciliae.
Glory-of-the-Snow or Chionodoxa luciliae.

Although they are referred to as ‘minor’ bulbs, these are actually the powerhouse of naturalizing. I have seen long-neglected gardens where the undivided perennials, overgrown shrubs and unpruned trees have failed but the Snowdrops, Crocuses and Grape Hyacinths continue to provide a dazzling spring display with no intervention at all; which is why every garden should make some space for these durable bulbs which include Snow Crocus (Crocus chrysanthus or tomassinianus), Dwarf Iris (Iris reticulata or danfordiae), Winter Aconite (Eranthis hyemalis) and Glory-of-the-Snow (Chionodoxa luciliae or forbesii). For those with a little more room to accommodate their precocious spread, English Bluebells (Scilla nutans) which also come in white and pink-flowering forms, as well as Grape Hyacinths (Muscari armeniacum) and Striped or Siberian Squill (Puschkinia libanotica and Scilla siberica respectively) may be good options. Just keep in mind that smaller bulbs such as Galanthus nivalis or Snowdrops dry out quickly and should be planted as soon as purchased.

Snowdrops or Galanthus nivalis, Grape Hyacinths with Winter Pansies, Scilla nutans with white Bleeding Heart, Iris reticulata 'JS Dijt'

Botanical Relatives

Your other option for bulbs that naturalize well is to choose Tulips and Daffodils that are closely related to the species they were bred from. While often smaller in stature they more than make up for this with their floriferous spring displays. For tulips choose T. tarda (white with yellow edges), T. acuminata (flame-like blooms), T. chrysantha (red and yellow) or Tulipa pulchella (violet). Dwarf Daffodils that naturalize well include ‘Tete a Tete’, ‘February Gold’, ‘Jetfire’ and the double-flowered ‘Rip Van Winkle’.

Tulipa tarda, Narcissus 'February Gold', Tulipa acuminata

Fall & Tall

There are also a handful of true crocus which bloom in autumn, all of which naturalize well. Crocus zonatus (pink), C. speciosus (pale blue) and Crocus sativus (purple) which is also known as the Saffron Crocus, as its red stigmas are the source of that expensive spice. Colchicum autumnale is also commonly known as fall crocus but has much larger flowers, often reaching heights of 8” tall. These emerge in the fall and are followed by foliage in the spring. The most common varieties available include the species, ‘Alba’ (pure white), ‘Waterlily’ (double flowers) and ‘The Giant’ (10” tall lavender-pink blooms). Last on my last of bulbs that naturalize are two taller selections, one native to BC and the other to Himalayas. Both Camassia quamash (blue flowers, 12-14” tall) and C. leichtlinii (white, pale or deep blue, 30” tall) are native to meadows and open woodlands in western North America and the bulbs were once harvested by first nations as a food source. Fritillaria imperialis or Crown Imperial is one of the oldest bulbs in cultivation but is rarely seen in gardens today. The stately 2-3’ tall stems bear showy clusters of pendulous yellow (‘Lutea’) or reddish-orange flowers (‘Rubra Maxima’).

Crocus sativus or Saffron Crocus, Fritillaria imperialis 'Rubra Maxima', Camassia quamash, Colchicum autumnale, Crocus 'Ruby Giant',