Perennial Care Guide

Getting to Know Allium: The Tough Disease Resistant Ornamental Onion

Truly the only thing that makes one cry in the garden is the weeding. And it's true, because allium is one onion that will not make you cry over anything.

When the New Bloomers sit down to make our list of plants we trust, the ones we would put in our own yard without a second thought, allium is always there. And yes, The New Bloomers is what we call ourselves... we are nerds people.

Allium is almost embarrassingly easy to grow. If your soil drains, deer leave it alone, disease mostly ignores it, and it rewards you with these floating, orb-shaped blooms right in the middle of summer, when a lot of the spring show has already faded. It is the kind of plant that makes a brand-new gardener look like they know exactly what they are doing.

So let me peel it back for you. Onion puns!

What is allium (and why "ornamental onion")?

Allium gets its name from the Latin word for garlic. Onions, garlic, leeks, and chives are all alliums. The ones we are talking about here are their good-looking cousins, edible, but grown purely for what they bring to the garden.

The foliage is grassy and strap-like, forming dense green clumps. We asked Travis to describe it and he said a thin, spineless aloe, uhh OK. Sure Travis, maybe. Give a leaf a crush and you will catch a faint onion smell, but left undisturbed, the plant has no scent at all. That same oniony compound, by the way, is exactly why deer and rabbits, and your next vampire romance, will walk right past it.

The blooms are the showpiece: tight, globe-shaped clusters of tiny star flowers that float on slender stems above the foliage. The clumping types we grow are summer bloomers, putting on their show from roughly July into early September, and they are an absolute magnet for pollinators. We have watched honeybees, bumblebees, carpenter bees, and miner bees all working the same patch at once.

Allium is not a North American native. But we can tell you from years of watching our own beds that the bees, butterflies, and other pollinators did not get that memo.

A quick note on types

"Allium" covers a lot of ground, and it helps to know which kind you are looking at, because they are not all grown the same way. Here is the quick version.

For most gardeners, that is all the botany you need. The big thing to take away: the alliums we sell are summer-blooming perennials you plant like any other plant, not fall bulbs you bury and wait on. You get a real, growing plant that comes to you established and often ready to bloom.

A few of the varieties we grow

Here is a look at our current favorites — a mix of colors, sizes, and bloom times. Click any one to check availability and full details.

Millenium

The Classic · Purple/Pink · Midsummer

The one that put Allium on the map. The 2018 PPA Perennial Plant of the Year. Dense 15–20″ clumps topped with bright pink-purple 2″ globes from July into September. If you grow one allium, grow this.

Serendipity

The Newcomer · Purple/Pink · Midsummer

A Proven Winners relative of 'Millenium' with cooler blue-green foliage and bigger, fuller bloom-heads on slightly taller stems.

Bubble Bath

Big Flowers · Lavender · Summer

A trade-show find Emily and I could not pass up. Big, fluffy 3″ lavender clusters float over blue-green clumps with softly twisted leaves. A genuine showstopper in bloom.

Bobble Head

Chonky Spirals · Lilac · Mid-Late Summer'Bobblehead'

Big, chonky, and proud of it. Thick, substantial foliage and large globe-like lilac blooms that come on a touch earlier and last for weeks.

Rising Star Chive

Small Ornamental Chive · Rose Pink · Late Spring

A smaller, wispier ornamental chive with rosy-pink tufted flowers and slender foliage. Edible, easy, and a favorite of the bees. Lovely tucked among established plants.

Snowcap Chive

Petite Chive · Snow White · Late Spring

Crisp white tufts on tidy 12–15″ stems as spring winds down. It reseeds gently, and it is a clean, bright pick for cut arrangements.

See the full allium collection for current availability.

Picking the right spot — this is the easy part

Allium is easy. There is really only one rule you cannot break, and we will get to it.

Light

Allium loves full sun and will happily take it. It also tolerates part shade, but the more sun it gets, the more blooms you get and the sturdier the stems stand. If you have a hot, bright spot that fries other plants, allium will be thrilled there. (If you want to nerd out on light like we do, here is our take on understanding sunlight for plants.)

Soil

This is the one rule: the soil has to drain. That is the whole secret to allium.

Here is the good news. Allium does not care about fertility. Poor soil, rocky soil, heavy clay, the barren strip by the driveway nothing else will grow in — allium will tolerate all of it. What it will not tolerate is wet feet. Soil that stays soggy or holds standing water leads to crown and root rot, and rot is the one thing that reliably kills an otherwise bulletproof plant.

So if you have soil that sits wet after a rain, it might be better to consider another plant. If not work in some grit and compost to open it up, or plant on a slight mound so water runs off. Add drainage. Not sure what you are working with? Our at-home soil test will tell you in an afternoon. But the short version is simple: if water drains, you are in business.

Planting your allium

Once you have a spot that drains, planting could not be more straightforward. Dig a hole, loosen the soil, and set the plant so the crown — where the roots meet the stems — sits right at soil level. Backfill, firm it in gently, water it well to settle the roots, and add a light layer of mulch. That is it. (Want the full walkthrough? See how to plant a new perennial.)

For the clumping types, allium looks best in groups rather than as a single lonely plant. We recommend planting in clusters of 3 to 5, spaced roughly 12 to 18 inches apart. That gives you a 2 to 3 square-foot drift of foliage with those globes floating above it — which is when allium really earns its keep.

Ongoing care

Here is the part where we disappoint anyone hoping for a long chore list. Once established, allium asks for almost nothing.

Can you actually eat it?

You can. These are true members of the onion and chive family, and the clean green foliage is edible. Snip a little, give it a rinse, and chop it into a pasta sauce, a soup, or some scrambled eggs — the ornamental chives especially. Will it blow your mind? Probably not. But foraging a little flavor from your own garden is a genuinely fun bonus.

One sensible caveat, because we are the honest type: only eat plants you have grown yourself without any chemical treatments, and never eat anything from the garden you cannot positively identify. The ornamental onions and chives we sell are all in the edible Allium genus — but when in doubt, admire them and leave the snacking to the bees.

A quick word on those "giant" alliums

You have probably seen them: the enormous purple softball-sized globes on tall stems, the ones that look almost too dramatic to be real. Varieties like 'Globemaster', 'Gladiator', and 'Purple Sensation'. They are impressive, and we get the appeal.

Two honest things to know. First, those are spring-blooming bulbs you plant in fall — a completely different process from the summer-blooming perennials we grow and ship. Second, and we will just say it: companies love to exaggerate the size and density of those globes in their photos. They are striking in person, but go in with realistic expectations and you will not be disappointed.

Quick troubleshooting

Our take

Allium is the plant we hand to nervous beginners. It is genuinely hard to kill as long as your soil drains. It carries the garden through the heart of summer when a lot of other things have checked out. Deer ignore it, pollinators swarm it, and it manages to look intentional and designed even when you have done almost nothing to earn it.

We grow a lineup of our favorites as established 1-gallon plants — pick a few, group them in threes and fives, give them a sunny spot that drains, and let them do their floating-orb thing. We think you will be hooked the same way we are.

Photo credit: Walters Gardens, Proven Winners, Stonehouse Nursery, Intrinsic Introductions and our own garden.

Have a question about whether allium is right for your yard? Email us at support@newblooms.com — we are always happy to help.