Zinnia

81121The same cooling weather that is initiating fall color is what finishes the zinnias that bloomed so colorfully through summer. Like tomatoes, they can stay out in the garden until they succumb frost if they continue to perform, and if the space they occupy is not needed for something else. There should be no guilt with replacing them sooner. After all, they are technically warm season annuals.

Some of the more popular types of zinnias are identified as Zinnia elegans or Zinnia violacea. Most are known merely by their variety name. They have been bred so extensively than it is difficult to assign any of them to particular species. Most are susceptible to mildew if crowded or watered from above. They want full sun exposure and rich soil. Seed can be sown immediately after frost.

Zinnias are crazily variable. Some get more than three feet tall. Others are less than a foot tall. They can bloom in every color except blue. Some resemble other types of daisies, with distended centers. Others are as fluffy as African marigolds. Some bloom with small but profuse flowers. Others have fewer but bigger flowers that are wider than three inches. Most are excellent cut flowers.

German Primrose

81114Just 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.

African Marigold

81107French 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.

Dwarf Carnation

81017The 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.

Cool Season Annuals Are Next

81017thumbGardening 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.

Mulla Mulla

81010The 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.

Annual Dahlia

50930They 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.

Annuals Change With The Seasons

50930thumbLike it or not, the warm season annuals that were so flashy all through spring and summer will eventually need to be replaced with cool season annuals to provide color through winter. It is always unpleasant to pull up the annuals of a previous season while they are still blooming, even if they are already getting scruffy and discolored. It is actually easier if they got roasted by recent warmth.

Some warm season annuals last longer than others. Many are actually perennials that can be overplanted with new cool season annuals as they get cut back or go dormant through their ‘off’ season. Some cur back perennials may not survive through winter; but those that do can regenerate next spring, just as the cool season annuals that obscured them all winter are finishing.

Wax begonias, for example, are warm season annuals that can continue to bloom until they get frosted. Where sheltered from frost, they only need to be cut back because partial defoliation exposes knobby bare stems. If they can be hidden by pansies or violas through their bare phase, they never need to be removed, and some will be happy to regenerate in spring.

Conversely, cyclamen, sweet William, chrysanthemum and some primroses are cool season annuals that have the potential to survive under the lush growth of warm season annuals next summer; but that is a topic for later. (Some people are allergic to primroses like poison oak.) Iceland poppy and ornamental cabbage and kale are not so perennial, but are quite colorful through winter.

Alyssum and nasturtium really are annuals that do not survive much more than one year. However, they can perform through summer where sheltered from heat, or through winter where sheltered from cold. In ideal situations, their self sown seedling replace deteriorating older plants, so that they can perform throughout the year. Nasturtium should be planted as seed, not from cell packs.

Calendula is a popular cool season annual early in the season, but may not last through the end of winter. Yet it is popular because it is so excellent through autumn. Chrysanthemums are even flashier, although they are often replaced as soon their first bloom phase finishes.

Start Cool Season Annuals Early

30925Twice 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.

Fernleaf Yarrow

70830‘Moonshine’ is probably the epitome of fernleaf yarrow, Achillea filipendulina, even though it is technically a hybrid. From the middle to the end of summer, its three inch wide corymbs (flat-topped trusses) of tiny bright yellow flowers stand as high as three feet above ferny and gray basal foliage. Bloom is best in full sun and warm exposure. Established plants do not need too much water.

Most varieties of fernleaf yarrow also bloom with bright yellow or gold flowers. Some might bloom with pale yellow, rosy pink, pale pink, reddish, white or pink and white flowers. All are good cut flowers, and can be dried. Some varieties are more compact. The most compact varieties work nicely in planters of mixed perennials. Butterflies and hummingbirds find them wherever they are.

Pruning out deteriorating blooms may promote sporadic subsequent bloom until autumn. However, some plants may bloom all at once, and then not bloom again until the following summer. Large blooms on the most vigorous plants may need to be staked. New plants can be propagated by division from mature plants. ‘Moonshine’ and many other cultivars are sterile. Others might self sow.