Companion Planting Series: Part 3 - The Onion Family
In today’s post we’re going to talk about the Onion family because they are one of the most important plant genera of garden plants for three major reasons; the genus contains herbs, vegetables and ornamental options. All of the Allium genus is found under the Amaryllidaceae family which means that those big red or pink Amaryllis you have out in your yard are cousins. The Allium genus itself is composed of monocoltyledonous flowering plants with about a thousand accepted species and this means it’s the largest genus in the Amaryllis family. In short for just about every need there’s an Allium. So what makes and Allium an Allium? Well, they are mainly characterized by the presence of a bulb, and potentially fragrant long-lasting flowers as well as a resistance to grazing animals due to compounds they contain called lachrymatory chemicals. These compounds are a chemical defense that is easily volatilized and become airborne or stick to fur, skin or clothing and over stimulate the tear glands. How that works is that a compound called Allinase breaks down to produce two other organic chemicals called syn-propanethol-s-oxide and Lachrymatory-factor synthase. This is what makes you tear up while cutting onions in the kitchen and if an onion is harvested at the wrong time of year it can have a tear gas like effect despite tear gas using different chemicals.
Beyond this the Bulb of an Allium is worthy of description because it’s not like the Corms of Gladiolus or the tubers you see on Potatoes. The outermost dry skin of an Allium bulb is called the tunic and it is what most of the inner layers will become if the plant lives long enough. The inner layers are called Bulb scales and they are fleshy modified leaves that exist to store carbohydrates and water for the Allium’s survival and growth they also act as a protective layer for what is at the center. At the center of things is a shortened modified stem which produces the growing point from which the green stalk and leaves emerge out of the often pointed tip of the bulb. At the very bottom is a hard layer called the Basal Plate, this area contains specialized cells that are geared towards producing what are called Adventitious Roots because they only emerge when there is contact with moisture or the soil. It is off the Basal Plate that offsets or Bulbels will emerge; these bulbels are a form of asexual reproduction where your Allium is effectively cloning itself. In some cases, Alliums are known to produce small bulbs on their stems as is seen in the case of Egyptian Onions. This is also a form of asexual reproduction and is a clone of the parent; these tiny bulbs are called Bulbils. Oddly Egyptian Onions take it even further, and may produce flowers from stems atop the bulbils just to make sure there is a next generation. This is where quantifying the Allium’s lice cycle gets a little hazy, because Alliums grown for food are grown as annuals but are actually biennial or perhaps perennial. Alliums grown as ornamentals are typically considered to be perennial, though as a part of Allium’s nature that might not be exactly true. A lot of members of the Allium species cluster and produce bulbels and form entire colonies Chives and Garlic Chives are great examples of this. What you can’t see is if the original few bulbs are still there or if they’ve been replaced by successive generations, so they may appear perennial but may be living their best biennial lives and you might never know. Elephant Garlic is a good contrast, because they too in time will form colonies but if those colonies are not split eventually the center-most eldest bulbs eventually rot and the middle hollows out as the ring expands ever onward.
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| This is a Red Onion bought from the store, Red Onions are essentially a type of Common Onion. The red pigment makes for a good dye, and is good for you because of the Anthocyanins. |
So, about that companion planting stuff we were supposed to be discussing. Onions are a very reliable plant for use in companion planting, their main and best attribute in the garden is their sheer space efficiency. You can plant between 4 and 9 garlic cloves per square foot and if you’re not growing the larger species of culinary Onions, then 4-6 per foot of row is perfectly acceptable. If you’re growing the herbal Onions (Chives), then give them at least a square foot and watch them fill it. Above all else onions are great neighbors because they seldom become invasive and they help with the critter resistance of your garden. It is well-known that Onions work great with the Cabbage family but they also are knotted to go great with Beets, Swiss Chard, Strawberries, Tomatoes, Lettuce, Summer Savory, Chamomile but do not mix well with Peas or Beans. Your chief pest problem with Allium will be Onion Maggots which are the larva of the Onion Fly (Delia antiqua). However Onions, or their aroma and allopathic compounds will help mask Cabbage from their Cabbage Moth and Cabbage Butterfly problems.
Chives (Allium schoenoprasum) – Chives are one of the quintessential herbs for the garden, though growing them can be tricky as they are a bit temperamental and in our climate need regular irrigation. Chives pair well with Carrots and help in Apple orchards by preventing Apple Scab.
Chives, Garlic (Allium tuberosum) – Garlic Chives are the easier to grow cousin of Chives and are distinguished by having flat leaves that are not hollow. They pair well with the same things as Chives but spread faster, and some have said they get aggressive under certain conditions.
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| These garlic cloves are from the Garlic I sell at the market. They decided to sprout and once one in a bulb does, others soon follow and so they have to become seed Garlic. |
Garlic (Allium sativum) – Garlic has been a seasoning staple for ages and is easy to grow and does not really get any pests, unless you count envious neighbors who want some. Garlic is said to help in preventing borers when grown around fruit trees, be good with Roses and to, protect Tomatoes from Red Spider Mites.
Garlic, Bear (Allium ursinum) – Bear Garlic is a wild species of wild garlic that is native to Europe and Asia, but it was brought to North America via colonization. It is commonly also called Cow’s Leek because cows love to eat it but it can alter the flavor of milk from cows that have eaten it. It is suggested that it be paired with aromatic herbs.
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| These are two of the larger Elephant Garlic cloves from last year's harvest. Elephant Garlic can survive in dry storage for more than a year with no issues. |
Garlic, Elephant (Allium ampeloprasum variety ampeloprasum) – Elephant Garlic is the massive cousin of Garlic with a far milder flavor. While technically a type of Leek, it pairs best with vegetables such as Lettuce, Swiss Chard, Beets, Carrots, Arugula or Radishes.
Garlic, Society (Tulbaghia violacea) – Society Garlic is a special mention in this listing. It isn’t an Allium, but the bulbs have a very mild garlic flavor and its flowers are great for attracting pollinators.
Garlic, Wild (Allium vinale) – Wild Garlic is a bit controversial, it is generally considered a weed and can be found in lawns usually after the smell hits you after you’ve mowed it. Some sources suggest it can rapidly go invasive too so there is that to be considered before cultivating it. It is fully edible but can be very pungent.
Leeks (Allium ampeloprasum) – Leeks have a botanical synonym, (A. porrum) that may appear in some publications. Leeks are a heavy feeder by Allium standards, but they grow well with carrots and fast maturing radishes.
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| This Yellow Onion is of the variety 'Yellow of Parma'. It was one that was in a soup kit and the thing decided to sprout. |
Onions, Common (Allium cepa) – Whether Yellow, White, Red or Sweet/Vidalia, the conventional onions are a critical kitchen vegetable and seasoning. To add on to the general notes in the article above, did you know you can grind up the dried tunic to make an onion powder seasoning to rival the one you buy at the store?
Onion, Egyptian (Allium x proliferum) – Egyptian Onions are also known as Walking Onions, and humorously they are not from Egypt. It is thought they originally came from modern day India or Pakistan. Regardless of that it takes about a growing season to get these to size These are a cheap effectively perennial option for growing near any cabbage family that are being grown as biennials.
Onion, Green (Allium fistulosum) – Green Onions, which when fully mature are called Salad Onions follow the same rules as conventional onions in terms of companion planting but reach a harvestable state far faster and can be planted more densely.
Onion, Nodding (Allium cernuum) – Nodding Onions are essentially a wild form of Onion native to the Americas and as such there isn’t much about it being used in companion planting.
Onion, Ornamental (Allium species) – Oranmental Onions are considered inedible and are bred for extra-showy flowers and unique foliage. It can be assumed they offer similar virtues as the Common Onion.
Onion, Pregnant (Allium cepa variety aggregatum) – Also known as Mother Onions or Multiplier Onions, preganant Onions are very similar to Common Onions with one major difference, they produce offsets far more frequently. They provide the same benefits as Common Onions.
Onion, Wild (Allium canadense) – Wild Onions are hard to tell apart from Wild Garlic (A. vinale), look for a fibrous coat on the central bulb, no offset bulbels and leaves that appear near the base of the flowering stem. Presumably the same rules apply here as with Wild garlic.
Ramps (Allium tricoccum) – Ramps are that Carolina staple food that is eaten up in the mountains where if you eat too much the aroma gets in your sweat. The companion Planting options are all woodland plants because this too is a woodland plant
Shallots (Allium cepa variety aggregatum) – Shallots are often compared to Green Onions because of how they are sometimes used in cooking. Shallots are milder than Green Onions and fit in better with recipes that call for onion but need not be overpowered by onion flavor. They follow the same companion planting rules as Common Onions.
We have now covered the members of the Allium family that you are most likely to encounter when considering your planting plans for your garden this year. As I noted before Onions are space efficient, good at attracting pollinators and resistant to critters such as deer. They pair well the cabbage family and a few other vegetables and fruits and of course they aren’t that hard to grow. I know that changes are I missed a few of the alliums in this post and please reply with specific ones that I did not cover and I’ll provide companion planting information as best I can. In the next episode we start on the Asters and after that the mountain of mints.
