Members of the allium family are pretty easy to identify by the garlicky or onion-like odors they give off.
The leaves of the allium family are also easily identifiable. They are either hollow (onions, onion chives)…
…or bent at a 45 degree angle (leeks, garlic, garlic chives, elephant garlic).
Most allium members form bulbs underground, though some bulbs may be very small. They also form layers (eg. onions) or cloves (eg. garlic & shallots).
There are six basic species in the allium family that gardeners commonly grow in their vegetable gardens. These include:
With the exception of occasional crossing between varieties of A. fistulosum (Japanese bunching onions) and A. cepa (the rest of the ‘onions’), the only risk of cross-pollination is between varieties within each species.
In other words, common chives and garlic chives will not cross-pollinate. But two different varieties of common chives will. Leeks and onions will not cross-pollinate, but different varieties of leeks will cross-pollinate with each other.
Alliums fall into two basic groups: those that produce flowers and seed, and those that produce bulbs and bulbils.
Those that reproduce with flowers & seed (sexually)
- Common Onions
- Top-setting onions (occasionally)
- Bunching onions
- Common hives
- Chinese/garlic chives
Those that reproduce with bulbs/bulbils (vegetatively)
- Top-setting onions
- Egyptian onions (also known as tree onions or walking onions)
- Multiplier onions
- Potato onions
Alliums that produce flowers are pollinated by bees, flies, and other insects, and not by the wind. Hand-pollinating is time consuming with alliums, and must be done every day for 2 to 4 weeks to ensure good seed set.
Letting the insects do it is much easier. Be sure that there are no varieties nearby that will cross with your plants, and grow one variety from each species at a time for seed saving.
If you wish to save seeds from more than one type of onion, for example, save seeds from one onion the first year, and from another onion the next. Onion seeds will maintain 50% germination for about 2 years.
If you do choose to bag and hand-pollinate the flower heads, follow these steps:
1. In the morning, before noon, unbag as many flower heads as you can keep free of pollinators and other insects at one time.
2. Use a camel hair brush to brush the flower heads, one at a time, in a circular motion, making sure to get each flower head twice.
3. Repeat every day for 2-4 weeks.
With those alliums that reproduce vegetatively, it is almost inevitable that some bulbils will be left in the soil. If you plant another variety that produces bulbs in the same spot the following year, the differences between the two crops may not be apparent and the different varieties could become mixed.
Once the seed heads mature, they are easily dried by withholding water, particularly in dry climates. In humid areas, after withholding water for a time, you may need to cut the seed heads and allow them to finish drying on a tarp in an area not exposed to sunlight.
Bend the seed head into a brown paper bag before cutting the stem to avoid losing seeds. Whatever you do, be sure to harvest the seed heads before they shatter.