Seeds are amazing, one the size of a printed period can produce a 12-foot shrub in two years. Seeds range in size from a soot particle to a coconut, and they all have one thing in common: Inside is an embryo and enough food to feed it until leaves can take over. Botanist Carol Baskin says a seed is a “baby plant, in a box, with its lunch.”
Seeds develop from plant “sex,” pollen from male parts (anthers) landing on stigmas and then transferred to an ovary by styles (connected to stigmas). After that happens, flower petals drop off, as seeds are produced by the ovary. Pollen may be transferred by wind, birds or insects. If one plant’s flowers contain both male and female parts, the flowers are said to be “perfect,” even though the plant may be sterile to its own pollen.
When we buy seeds in bins or packets, they are dormant, waiting for moisture to spark germination. They are often brown or black, some beige in color, and all are dry.
Often we come across plants we’d like to duplicate, but the seeds are not quite mature, so we avoid taking them. We should take some of those still-green seeds, especially seeds of wildflowers we admire, to germinate them at home right away. We should not collect seeds from rare wildflowers, but leave them to replenish the “herd.” I think that is the law, especially on federal lands. But we often come across a large section of wildflowers, some still in blossom, others past. Those that have finished blossoming are producing seeds in place of flowers.
Seeds don’t have to go dormant to be viable. Botanist Dr. Kay Lancaster says“ With wild plants (as opposed to crops), it’s often easier to grow a new plant from immature seed than from mature.” She also said immature seeds may germinate much more quickly than those that have gone dormant. “In general, you cannot let the fruits of immature seeds dry and store them for any length of time; you need to plant seeds pretty much fresh off the plant,” she added. If the plant hasn’t completed filling the embryo’s lunch box, that’s OK, because it won’t be needed for as long as it would be for overcoming dormancy.
Wildflowers are unlikely to be hybrids, so the seeds should produce true copies of the parents. The possibility of gathering seeds from hybrids and getting an unexpected and unwanted plant from seeds is one reason not to gather seeds from private gardens without permission from the garden owner, who should warn you if it’s a hybrid. It’s also not courteous to pinch seeds without permission.
Why do seeds go dormant? To wait for a more favorable outlook for seedlings, such as non-freezing weather, abundant sunlight, or even the right season. Other reasons include waiting for dispersal of other seeds to avoid competition from sibling seedlings for water, nutrients and sunlight, or to germinate at a different time than other seeds produced by the parent plant.
Some seeds have special needs, too. Some seeds won’t germinate unless they’ve been scarified (seedcoat physically nicked or broken to permit germination) or stratified (exposed to cold temperatures for a specified time), or even subjected to fire. Some “fireweeds” only germinate after they’ve gone through a forest or range fire. Some seeds need company. Plants such as Indian paintbrush (Castilleja) only grow if there’s a close penstemon or grass it can parasitize. Roots of Indian paintbrush penetrate roots of such near plants, and get nutrients by sucking them from the neighbor’s roots.
In addition to dormancy, another factor barring seed germination is quiescence. Some seeds fail to germinate because environmental conditions are too cold, too warm, too light or too dark. Many weed seeds, for instance, need light to initiate germination. I’ve heard some Nebraska farmers prefer to run tractors and plow, disk or harrow in moonlight to keep weed germination at a minimum. Some weed seeds may lie in soil for many years, waiting for the right conditions, including light, for germination. Velvetleaf (Abutilon theophrasti), for instance, popped up in our yard after we’d gardened here for over 10 years, and had never seen that weed. Its seed has a viability of 50 years. Its seed pod is too large for bird planting. Light does penetrate soil deeper than we expect.
A recent seed surprise was the archaeological dig discovery of a clay ball filled with squash seeds near Green Bay, Wis. The seeds were dated 800 years old, and some of them were given to students in Winnipeg to germinate. The students were successful, eventually producing a large, long, smooth-skinned fruit that turned orange at maturity. That squash was considered extinct prior to this season. The longest-dormant seed ever germinated was a date seed recovered from Masada in Israel, said to be 2,000 years old.
Send garden questions to email@example.com or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.