UNITED STATES—Plants could not proliferate as they do if they were as unintelligent as they seem to be. Actually, much of their activity would be considered quite ingenious if it could be observed in a more ‘human’ perspective. From their exploitation of pollinators to their aggressive tactics for competition with other plants, the behavior of plants is obviously very deliberate and purposeful.Because they are so reliant on the weather, pollinators and so many other environmental factors, the life cycles of plants are on strict schedules. They must also adapt to diseases and all sorts of other pathogens. Fires and grazing animals are problems for many, but advantages to most.
Most seeds develop during summer and autumn. When they fall to the ground, they need to know to delay germination until spring to avoid frost and the likelihood of getting eaten. Seeds of many plants, particularly those from more severe climates, germinate only after being ‘stratified’ by a specific duration of cold weather. Such seeds need to be artificially stratified by refrigeration in order to germinate any differently from their natural schedule, or where winters are not sufficiently cold.
Many seeds require ‘scarification’ by digestion by animals that naturally eat them, or by the quick heat of a wildfire, to break or soften a hard outer coating that otherwise inhibits germination. Seeds that need to be digested actually rely on animals for distribution. Seed that need heat want to be the first to regenerate after a wildfire, before competing plants recover.
Goldenrain tree, and many maples and pines produce so many seeds that even if less than one percent germinate in the garden, they seem to be prolific. However, for more reliable germination of a majority of seeds, they should be scarified. The seeds of many pines that crave fire can be heated briefly in an already hot oven to simulate fire, just enough to heat the seed coat without roasting the seeds. Some people actually prefer to spread them on a piece of paper, and then burn the paper. Seeds that only need their hard outer coating to be damaged slightly might need only to be sanded lightly on sandpaper. I actually prefer to rub my canna or Heavenly bamboo (nandina) seeds on a brick or bit of sandstone.
Although not directly toxic, canna has a unique reputation of lethality. Its spherical seeds are so hard that they were historically used as shot. Many victims are now pushing up daisies. Those who survived were pulling out cannas.
Old fashioned varieties that get up to six feet tall seem to be at least as popular as shorter modern varieties that get less than half as tall, probably because their bold foliage is as appealing as their colorful but awkwardly structured flowers. The big leaves can be cool green, rich reddish bronze or variegated. Red, orange, yellow, pink or rarely white flowers that bloom from summer to autumn are striking amongst the lush foliage, but are too perishable to be good cut flowers.
Stems that have finished blooming should be cut to the ground to promote more colorful new foliage and bloom. Mature colonies (of rhizomes) can be divided while dormant through winter if they get crowded enough to inhibit bloom every few years.
By Tony Tomeo