Growing self-seeding plants is the second best technique to saving seeds for planting later. Yes, exactly as the term implies, self-seeding plants sow their own seeds resulting in more to enjoy each year. Would it not be best to bypass the extra labor to harvest, clean, dry, and store seeds? When attempting to naturalize a big field with wildflowers, then self-seeding is the best option. However, growing self-seeding plants can also have its downfalls. When plants are allowed to self-seed, the very prolific varieties might take over your garden more than you bargained for. In addition, you have no control over where they may seed themselves. Some can throw their seeds quite a distance. They could end up in the middle of your driveway, in your vegetable garden, over the fence in your neighbor’s yard, or scattered thousands of feet or even miles away by wind and birds.

If you want the benefits of growing self-seeding plants, this could be your opportunity to compromise with Mother Nature. Instead of making her do all the work, offer to lend a helping hand and you will be able to place the seeds where YOU want them to be. You can actually take advantage of self-seeding and seed saving at the same time. If there are too many seeds when harvesting for self-seeding, some can be saved as a safeguard for germination failure in the spring or to share with friends. (For more information on saving seeds, see my article: “Save Seeds, Save Money, Save Life”)

Self-seeders drop or throw their matured seeds to the ground where they overwinter until proper conditions trigger sprouting in the spring. There are self-seeding trees, flowers, herbs, fruits and vegetables. They can be annuals or perennials and you will want to know which they are so as not to crowd next year’s plants. Annuals only grow for one year so new seeds can replace the existing plants. Perennials will come back the next year so new seeds should be spaced accordingly. Extra may be planted to compensate for potential germination failure due to abnormally harsh conditions. However, if the germination rate is very successful, seedlings will probably need to be thinned to avoid overcrowding.

To increase the success rate, clean the anticipated planting area of any large debris and loosen the soil. The trick is the timing in emulating Mother Nature. Seeds need to be mature but harvested before they disappear from the plant and seed themselves. This typically requires daily monitoring as the seeds are developing. Depending on the size of the plant and seed casing, preventative measures can be taken to avoid losing the seeds by enclosing the seed casings in a clear plastic bag. This should only be done a couple days before suspecting that the seeds will naturally fall off overnight, otherwise lack of proper air circulation and trapped moisture could prohibit good maturation of seeds. With trees, the seeds will likely fall to the ground but should be collected within the same day and moved to the desired location.

In nature, the seeds would land on soil beneath the parent plant and rest until spring assuming they are not blown away by the wind or carried away by birds. The parent plant would die off and provide natural protective mulch. They might also land in a field between tall grasses to help protect them against harsh winter climate, be covered by a thin layer of leaves or pine needles, or walked on and pushed firmly into the soil. As soon as the seeds are collected, sow in the desired location. To protect the seeds from the wind, lightly cover with soil and press firmly. Allow any further protection to happen naturally. It would be wise to mark the planted area with sturdy markers or make a sketch on paper or computer. Be careful not to dig up or disturb the seeded area in the spring before the seeds sprout.

So how does one know if a plant is self-seeding or not? Most resources listing individual plants such as a plant encyclopedia, online plant database, or retail catalog should state whether a plant is self-seeding. I have provided a partial list to get you started. Keep in mind that zone hardiness for any self-seeding plant applies. If a plant is self-seeding and hardy to zone 7 but you live in zone 2, the seeds will not be able to withstand the climate any more than the parent plant. Many self-seeders can be invasive and spread too quickly. Before planting, check with the county weed management or extension office to be sure a specific plant is not on the list of banned noxious weeds for your county or state.

Flowers
amaranth
calendula
candytuft
columbine
cleome
cosmos
daisy
forget-me-nots
granny’s bonnets
hellebores
hollyhocks
lambs ears
mallow
marigolds
nasturtium
phlox
poppy
primulas
sunflower
verbena
zinnia

Fruit/Vegetables
With the right conditions most any fruit or vegetable with seeds (melons, cucumbers, tomato, peppers, etc.) left behind in the garden will self-seed.
asparagus
most greens

chokecherry
loquat
mulberry

Herbs
basil
borage
burdock
calendula
chamomile
dill
fennel
feverfew
lemon balm
most mints
parsley
valerian

Trees/Shrubs
date palm
golden rain tree
holly
olive
pigeon pea
maple
russian olive (not actually an olive and becoming invasive in some locations)
senna