Alliums (Ornamental Onions)
Type: Perennial Bulb (Zones 3-8).
Light Requirements: Full to Part Sun (some will work in Part Shade)
Moisture/Soil: Average moisture.
Blooms: Late spring to early summer (varies by variety)
Size: Height: Varies by variety. Purple Sensation grows to about 30″ in part sun and full sun in my yard.
Additional Info: I grow several varieties. I love them and as a bonus the critters tend to not bother them (because of the onion smell).
Pros: They are very low maintenance and pest resistant. Most varieties are also quite reasonably priced (less than $1 a piece). Additionally you can leave the dried seed heads on to provide additional interest. Also they don’t need stacking.
Cons: I can’t think of any.
Varieties: There are a LOT of varieties to choose from. I recommend picking several from different blooming periods.
‘Purple Sensation’ - 20″-30″ tall, baseball sized flowers, blooms late spring (can be grown in part shade). Quite reasonably priced.
‘Sphaerocephalon’ (drum stick) - 18″-24″ tall, golf ball sized flowers (reddish purple), blooms mid summer, very old variety, looks best when large quantity are planted. I have quite a few of these. The leaves look like onion grass, so be careful not to pull them out when weeding (which I have done). Very inexpensive!
‘Schubertii‘ – 18″ tall, volleyball size flowers (light purple), blooms very late spring (mine will probably bloom in a week or so). These are magical looking. They are kind of short on the stem, so they need to be towards the front of th e bed so they aren’t hidden by something else, but the flowers are enormous and very interesting.
‘Neapolitanum’ – 12-14″ tall, quarter size flower (white), late spring. Inexpensive, should be planted in mass.
Others (come in colors ranging from purples to white with a couple of varieties in yellow and pink) : Globemaster (extra large and pricey), Christophii, Ambassador, Graceful…
Interesting Pairings: For a couple of interesting companion planting ideas check out www.plantswise.com and her beautiful combination of coral bells/heuchera ‘carmel’ with Allium karataviense and Artemisia with Allium sphaerocephalon. Apparently the heuchera ‘carmel’ (which I have quite a bit of) can grow in a more sunny location (mine grow in part shade). I may still try this out in the fall.
*The Plant of the Week is based on plants that do well in my 7a/6b garden in SE Pennsylvania.