Annuals are plants that complete their entire life cycle from germination to death within a single year. Biennials complete their entire life cycle in two years, mostly by developing vegetative growth during their first year, and then blooming, producing seed and then dying after their second year. Perennials are the many herbaceous plants that survive longer than just a few years or indefinitely.
As simple as these definitions seem to be, the plants that they describe are a bit more complicated. Some biennials can regenerate from the roots of plants that have already bloomed and died. Stems of some annuals can root where they touch the ground, to form new plants that survive for another year. Some annuals seem perennial if they replace themselves with their own seedlings.
Of course, none of that matters for the many biennials, perennials and self perpetuating annuals that get grown as mere annuals. At a time when ‘sustainability’ is a fad and trendy buzz word, it is ironic that so many bedding plants that could contribute more if given the chance to do so, continue to get discarded as soon as their primary season finishes. Most have more potential than that.
Self perpetuating annuals like sweet alyssum and nasturtium might only need to be groomed of old plants as new ones take over. Young nasturtium are rather efficient at overwhelming their own parent plants to some degree. Of course, subsequent generations will revert to feral plants. Fancier nasturtium will eventually become basic orange and yellow. Sweet alyssum will be plain white.
Many annuals that are actually perennials might survive through their off season if just overplanted with more seasonal annuals, and then regenerate when the weather becomes more favorable. For example, primrose from last season might be left in the ground as petunias take over for summer, but when the petunias finish next autumn, the primrose can regenerate for another season.
Such perennials regenerate more randomly than they grew in their primary season, and will need some degree of grooming and perhaps mulching.
Oh, how breeding complicates things. Many years ago, there were only six basic types of wax begonia, Begonia semperflorens-cultorum, with three choices for floral color, and two choices for foliar color. Bloom was white, pink or red. Foliage was either green or dark bronze. Although these choices have not changed, some modern hybrids are difficult to distinguish from other species.
Wax begonia can be either a cool season annual or a warm season annual, depending on when it gets planted. It can be grown as a short term perennial if pruned back in both early spring and early autumn. By spring, winter growth is tired of the cold. By autumn, summer growth is worn out from warmth. Exposed plants can get lethally frosted in winter or roasted by sunlight in summer.
Therefore, wax begonia prefers to be somewhat sheltered. It is more tolerant of full sun exposure in summer if mixed with other annuals or perennials. Too much shade compromises bloom. Wax begonia expects richly amended soil and regular watering, and is just as happy in pots as other annuals are. Potted plants can be moved to sheltered spots when the weather gets too hot or cold.
Just like African marigold that was featured earlier is actually Mexican, German primrose, Primula obconica, is actually Chinese. As odd as it is, the common name is an improvement from the former name of ‘poison primrose’, which was derived from the potentially irritating sap of the unimproved species before it was bred to be less toxic, as well as more colorful and prolific in bloom.
Here where winters are mild, German primrose is a short term perennial that is mostly grown as a cool season annual. Most of us do not bother to keep them alive as their foliage deteriorates in warm spring and summer weather. It is easier to plant new ones next autumn. They want rich soil and regular watering until rainy weather takes over. Deadheading promotes subsequent bloom.
Foliage should not get much higher than six inches. Flowers stand a few inches higher, and can get almost as high as a foot. Individual flowers can be as wide as an inch, and they bloom with several others in domed trusses that might be a few inches wide. Bloom can be white or pastel hues of pink, lavender, blue, peachy orange, salmon, rose or soft maroon, some with white edges.
French Marigold might have been a more appropriate choice. It is the official flower of Dia de los Muertos on November 2. Some might say that the bigger and bolder African marigold, Tagetes erecta, is just as official. Both are Mexican, but as the names imply, most varieties of French marigold were developed in France, and most varieties of African marigold were developed in Africa.
Both African and French marigolds are warm season or autumn annuals that exhibit a similar range of floral colors that contrast nicely against their rich green aromatic foliage, but they are not much more similar than that. African marigold can get almost three feet high and two feet wide. Its bigger pom pom flowers tend to be solid colors rather than mixed; and vanilla white, although unpopular, is not rare. Bright yellow and bright orange are the most familiar. Rusty red is the third most popular color.
African marigold wants rich and well drained soil in sunny exposures. It gets lanky, blooms less, and is more likely to mildew where partly shaded. It should be watered regularly and early in the day. Flowers can mold if they stay damp for too long. Deadheading, which is the removal of deteriorating flowers, promotes continued bloom. Occasional application of fertilizer might also help.
The three most popular specie of Dianthus are sweet William, garden pink and carnation. Sweet William and garden pink are light duty perennial bedding plants that are often grown as annuals. Carnation blooms are more familiar as fragrant cut flowers than as home garden flowers. Then there is dwarf carnation, Dianthus caryophyllus, that combines the best characteristics of all three.
Unlike the varieties of carnation that are grown for cut flowers on long stems, dwarf carnations do not need to be staked. Their compact growth gets only about five or six inches tall, and not much wider; so they are delightful summer and autumn annuals, or short term perennials like sweet William and pink. Yet, the two inch wide flowers are fragrant and as colorful as cut flower carnations.
The double or semi-double flowers can be white, pale yellow, pale orange, maroon, scarlet, red, peach, rose, or most popularly, various hues of pink. Bloom begins late in spring and continues through autumn and almost until winter. Stray flowers can bloom anytime. The narrow leaves are slightly bluish green, with an almost rubbery texture. Deadheading keeps well blooming plants tidy.
Gardening is not always fun. After diligently tending to warm season vegetables through spring and summer, it eventually becomes necessary to pull them up to relinquish space for cool season vegetables that grow through autumn and winter. It likely would be less unpleasant to wait for them to succumb to frost, but by that time, it would be getting late for the incoming vegetable plants.
Removing warm season annuals and bedding plants is just as necessary, and might be just as unpleasant. The only consolation is that the incoming cool season annuals and bedding plants are likely to be blooming well as they get installed. Even though they take a while to mature, there is no time without at least some degree of color. Warm season annuals may be tired by now anyway.
Just like cool season vegetable plants, the various cool season annuals and bedding plants appreciate an early start so that they can begin to disperse roots while the soil is still somewhat warm. Only those that dislike warmth should wait. Cyclamen and flowering cabbage and kale can be planted as late as winter. Flowering cabbage and kale might even bolt if they get too warm too soon.
Pansy, viola, sweet William, stock, Iceland poppy, calendula and various primroses are all seasonable now. They should be happy to bloom until they too need to be replaced by annuals for the following season, several months later. Chrysanthemum, marigold and a few other autumn annuals are short term annuals that bloom excellently through autumn, but are not likely to bloom later.
Just like most of the cool season vegetables, most of the cool season annuals should be planted as small seedlings in cell pack. Chrysanthemum and many of the primroses, as well as cyclamen and flowering cabbage and kale that come later, should actually be planted as four inch potted plants. Needless to say, some of these are expensive relative to their respectively limited bloom seasons. Seed for nasturtium and alyssum can be sown directly into the garden. Nasturtiums seedlings in cell packs are expensive and do not transplant well.
The common name sounds funny, but it is easier to pronounce then than the Latin name. Mulla mulla, Ptilotus exaltus, is an Australian species that has been locally available longer than its limited popularity suggests. It may seem to be more peculiar than it is because it is grown primarily by specialty growers, who happen to grow many cool plants that should be more popular than they are.
Like many species that are grown as annuals, the mulla mulla is really a short term perennial that can perform for a few years, but is unfortunately more often grown as a warm season annual. It will finish blooming soon, but if left in the garden through winter dormancy, young plants should resume in about April or May. It can succumb to frost if the weather gets cold enough through winter.
Although it can survive with less, mulla mulla prefers somewhat regular watering, and good sun exposure. New spring growth develops rather vigorously without getting much more than half a foot high and wide. Fuzzy cylindrical blooms that stand above the foliage are about three inches long. Floral color is pinkish mauve, with a silvery sheen. Deadheading promotes subsequent bloom.
They are really just smaller versions of the larger perennial dahlias that are grown for their big bold flowers and flashy colors. Technically, annual dahlias produce smaller versions of the same perennial roots that can survive through winter to regenerate the following spring. Yet to most of us, it is easier to purchase new plants in spring than to grow new plants from stored roots.
Relative to larger dahlias, everything about annual dahlias is subdued. The flowers are neither as big, nor as variable. They can bloom any color except blue or green, but are usually simple shades of red, orange, yellow, pink or white. Their main advantage is that they do not get much more than a foot tall, so they fit into more situations and do not need to be staked.
Bloom starts rather late in spring and continues until about now. Some varieties have bronzed foliage. Fertilizer promotes bloom and healthy foliar color; but too much nitrogen can inhibit bloom. Dahlias can be happy in pots, but only with good drainage and regular watering.
Twice a year, it becomes necessary to discuss the unpleasantries of pulling up the flowering annuals (as well as vegetable plants) of one season, to relinquish space for those of the next season. Just a few months ago, cool season annuals got replaced with warm season annuals. Now, those same warm season annuals will get replaced with cool season annuals for the next few months.
It is unpleasant because the outgoing annuals are probably still blooming when it is time for them to go. It might be easier to wait for cool season annuals to get roasted by hot weather, or for warm season annuals to get frosted. Unfortunately, by that time, the incoming annuals would be at a disadvantage. Hot or cold weather is also uncomfortable for plants that are not yet established.
Sure, warm season annuals like warmth, but only after they have sufficiently dispersed their roots to sustain their growth during warm weather. This is most efficiently accomplished while the weather is still mild earlier within their season. Cool season annuals likewise do not mind cool weather, but do not grow as well as they do during the warmer weather earlier within their season.
This is why it is better to plant pansy, viola, sweet William, Iceland poppy, stock, calendula and the various primroses earlier rather than later if possible. There is no exact science here. A forecast for warm weather certainly justifies delay. Cyclamen and ornamental cabbage and kale are a bit more sensitive to warmth, so could wait a bit longer. They grow well through cold weather anyway.
Chrysanthemum, alyssum and nasturtium are odd ones. Chrysanthemum, although perennial, is most often planted as a short term autumn annual while it is already blooming or is just about to bloom. It rarely gets a second chance if it finishes bloom before winter. Alyssum and nasturtium can be both warm and cool season annuals. They only gets replanted this time of year because individual plants perform through one season or the other, but probably not both. Nasturtium should be grown from seed.
Not all annuals last as long as petunias do through summer, or pansies do through winter. Some fill in for the in between seasons, or if longer term annuals do not last quite as long as they should. Cockscomb, Celosia plumosa, blooms best now that it is about halfway through summer, and then finishes as weather gets too cool for it in late autumn, not so much more than two months later.
The common name of cockscomb is actually derived from another species, Celosia cristata, which blooms with oddly stunted and flared blooms that supposedly resemble the combs of roosters, but the most popular varieties are so stunted that they actually look more like little fuzzy brains. Celosia plumosa blooms are more feathery, like those of pampas grass, but only three inches long.
The red, orange, yellow and pink blooms are as brightly colored as a pinata. Mixed colors, which might include softer pink, are the most popular for six packs and seed. White is notably lacking from popular mixes, and is only rarely available separately. Some varieties have bronzed foliage. Cockscomb lasts more than a week as a cut flower, but blooms on rather short and stout stems.