Puslinch Pioneer Article September 2023
I would like to grow some of the ornamental onions that I’ve seen in other gardens. Can you suggest different types and how to grow them?
The Allium family includes garlic, leeks, chives and edible onions as well as these
highly ornamental onions. Ornamental onions aka Alliums are a great addition to
any garden.
These ornamental onions are bold and architectural, with large
rounded heads of usually purple flowers, followed by attractive seedheads.
Weave them through sunny borders or combine them with feathery grasses for
best effect. They range in height from 30 cm to 120cm. Alliums look great massed
together with their whimsical flower heads. They have showy flowerheads in a
wide range of colours like purple, mauve, blue, pink, burgundy, yellow and white.
Alliums bloom times range from May to August depending on variety. The flowers
make great cut flowers. The dried flowers are lovely in a vase.
Plant Alliums in the fall in well-drained soil. Planting depth varies depending on
the size of the bulb. Check package instructions for planting depth and spacing.
Alliums should be planted with their roots down. If you can’t see the roots, plant
with the flat side down in the hole. Alliums need full sun, 6 or more hours of
direct sunlight. Alliums are drought tolerant once established. Alliums will
multiply over time; clumps can be lifted and separated. Some alliums will
naturalize by seeding around. Dead head your flower heads if you don’t want
seeding to occur.
Ornamental onions smell like onions or garlic when their foliage is bruised. As a
result, rabbits and deer tend to avoid alliums due to their smell. They are toxic if
eaten by cats, dogs or horses.
The following will help you find the right alliums for your garden.
For spring:
The tallest allium is Allium gigianteum having a large ball of purple flowers.
It is about 120 cm in height and blooms in late June, early July.
White flowered Mount Everest and purple flowered Globemaster are 80 cm
tall and bloom May/ June.
Allium bulgaricum is an interesting allium with clusters of purple and white
bell-shaped flowers which bloom in June. The flower of Allium christophii
aka Star of Persia is a gorgeous silver mauve collection of star flowers. They
are fabulous as dried flowers.
Allium caeruleum is a divine true blue which flowers in May/June. Allium
schubertii aka tumble weed onion has a weird funky mauve flower head. It
makes a playful addition to your May/June garden.
There are several alliums that flower in to the summer:
Allium flavum has yellow fireworks like flowers and is only 30cm high.
Allium cernuum aka nodding onions is a native allium with pink flowers.
Allium sphaerocephalon aka drumstick onions have burgundy flowers
which look great massed with grasses.
The rosy purple flowered Allium millennium is the last onion to bloom in
the summer and it looks amazing in the front of your garden.
The flower heads of alliums are made up of many small flowers, this makes them
very appealing to a wide variety of bees, butterflies and other pollinators.
Consider adding a few ornamental onions to your garden.