Soon after I joined Dave's Garden, someone gave me a pregnant onion plant. What a surprise to realize as a not-so-novice gardener that I had never heard of this interesting, easy-care potted plant for inside or out.
I thought I knew about a lot of different plants until I joined Dave's Garden. I've since discovered many more plants out there in cultivation than are shown in most standard general houseplant books! I was given a pregnant onion (Ornithogalum longibracteatum) at my first plant swap, by the first DG member I met in real life, Gitagal. I've since discovered that this decorative onion is easy to grow on a windowsill or outside for the summer, and easy to share from tiny new bulbs.
Amazing baby onions
Two years ago, Gita offered me a tiny baby onion in its own little clay pot. Who could resist the precious tiny green thing or Gita's enthusiastic decriptions of this interesting, easy-to-grow pot plant? I did find the young, not yet officially pregnant, onion to be completely problem-free. It grew when I watered it and waited patiently when I didn't. I may have fertilized it; I'm not sure. My onion seemed content on any windowsill. It grew from one slim leaf to several long, arching, lily-like leaves. The tiny bulb swelled from a pea to a walnut, and without help from any other onions, became pregnant.
Pregnant onions start to reproduce at a somewhat tender age. Baby onions develop right on the sides of the mother plant's bulb, near or above the soil level. You might even detect a telltale bumpy swelling under the mother onion's skin as one or more babies grow. As the onion grows, its outer layer occasionally dries to reveal tiny baby bulbs that seem to be glued to the mother's side. These pea-size progeny eventually fall and root from the scabby bottom, and grow one first grassy leaf from the pointier end. It's incredibly easy to share pregnant onions when you pick out and pot up the babies as Gita did for me and other members in the Mid-Atlantic Regional Gardening forum.
Eventually, mother pregnant onions also grow side bulbs like a daffodil or amaryllis does. Maybe they're really underground babies that develop unseen; I don't know if anyone has investigated that. These side bulbs make their own set of leaves. After three years of my casual care, my itty bitty baby onion grew into a prolific mother, complete with two offset bulbs (aunts?) and a whole bundle of babies. When I'm lax in watering, the bulb may soften and shrivel a bit, but a cup of H20 has it plump in no time. The main and side bulbs are all flowering on a chilly, bright laundry room window shelf as I write this. Pregnant onion flowers are white and green, held in a cluster at the end of a long curvy stem. It's not a showy flower, but the long stems make a dramatic statement. Although seeds may develop, the plant is so easy and quick to propagate from baby bulbs that I doubt you'll care to save the seeds.
Between the offset bulbs and the many babies, a pregnant onion sure can fill a pot within a couple of years. Gita has used a large clay planter full of a few generations of pregnant onion as an interesting deck plant, with long arching shiny foliage and spreading flower stems. Tip out that pot to divide the plant and you'll find a tough, tangled mass of roots supporting the carefree greenery. Gita tells me that dividing a pregnant onion at this phase is a quite a wrestling match! Here are pictures she took that she took when she divided her big pot of pregnant onions.
Gita was shocked to see this tight mass of roots in a planter of pregnant onions. She was even more shocked by how tough they were to divide. "You practically destroy some of the plants to get these things apart! As you do work on this, the little baby bulbs just keep falling off like marbles....."
Gita is not the only Dave's Gardener to have discovered pregnant onions. She received her first pregnant onion from another Dave's Gardener a few years before passing them along. Here is the link to the PlantFiles page on pregnant onion. Many pregnant onion "grandparents" have shared comments from their experiences with this plant. Some grow it indoors all year. Others send it out for the summer and use it to fill a deck planter or hanging basket. Frost-free area gardeners can keep it in the ground in a flowerbed. While there is only one vendor listed for this plant, an amazing 42 subscribers have put pregnant onion on their "have" or "want" lists. Most of them are haves, an encouraging note if you're thinking of acquiring this plant.
If you receive a baby pregnant onion, press the bulb slightly into well draining potting mix in a small pot. The drapey leaves are displayed well if they can hang over a table or window edge, or spill from a hanging basket. Choose an indoor spot with reasonable amount of light, or an outdoor location in warm weather with a moderate amount of sun. Give it some water and maybe fertilizer, and start making new friends because in a year or so you're going to have a lot of baby onions to give away!
Please note: The Pregnant onion is not edible. It belongs to the Hyacinth family, not the true onion (Allium) family.
Resources and credits
Overwhelming credit goes of course to Gitagal, who generously shared her pregnant onion and expertise with me so I could write this article. (Okay, Gita, name your price!) The"root" pictures and planter picture were taken by and are property of Gitagal, and the others were taken by and are property of the author.
About Sally G. Miller
I grew up playing in the Maryland woods, and would still do it often if life allowed! Graduate of University of Maryland, my degree is in Agriculture. Gardens and natural areas give me endless opportunity for learning and wonder. Naturally (pun intended) my garden style leans towards the casual, and my cultural methods towards organic. I like to try new plants, and have "some of everything" in my indoor and outdoor gardens. Thanks go to my parents for passing along their love of gardening and nature, and my husband and kids for being patient when I get lost in the garden.