The longer and cooler nights of autumn will soon finish the season for zinnias. (Most, but not all of the common zinnias are of the species Zinnia elegans.) They are really at their best while the weather is warm through summer and the beginning of autumn. As the garden warms up at the end of next spring, new seedlings can be planted, or zinnia seed can be sown. They like rich soil and regular watering, but are susceptible to mildew in humid spots. Sunny areas with good air circulation are best.

Like related chrysanthemums, zinnias are quite variable. Although the simpler forms remain more popular; double, cactus flowered and crested forms are also available.  Flowers can be less than an inch wide to more than five inches wide. Their color range includes white, yellow, orange, salmon, pink, red, rose, purple, lavender and even green. The narrowly oval leaves can get to about four inches long. Compact types stay about a foot tall and wide. Large types get twice as wide and more than three times as tall. 

Busy Lizzie had been unavailable for years because of a downy mildew epidemic. It has only recently been regaining availability and popularity. During its absence, New Guinea impatiens, Impatiens hawkeri, became more popular. Although a closely related species of the same genus, the two are actually very different. Resistance to mildew is important.

Besides that, New Guinea impatien is about as foliar as it is floral. Its bolder and slightly bigger flowers are notably less abundant than those of busy LIzzie. Also, its floral color range is limited to white, pink, red, lavender, magenta or orange. Its rich green or bronze foliage below compensates though. Many cultivars are variegated with yellow or salmon.

New Guinea impatiens are unfortunately a bit more expensive than most other annuals. The smallest that are available are in four-inch pots. They are unavailable in smaller and less expensive cell packs. They can grow about a foot wide and slightly taller if crowded. During winter, they deteriorate; but they can be tender perennials with shelter from frost.

Simplicity is a recurring theme among wax begonia, Begonia X semperflorens–cultorum. Floral color is white, pink or red. Foliar color is green, bronze or dark bronze. Each floral color combines with each foliar color. Variation within this simple color range is minimal. So is variation of foliar or floral form. Cultivars with slightly fluffier double bloom are rare.

Perfection eliminated the potential for improvement. Regardless of such simple variation, wax begonia is among the most popular annuals. Technically, it is perennial. Technically, it prefers warm weather. It remains available as cool season color after summer because it blooms until frost. Later, it can recover from minor frost. Without frost, it blooms all year.

Mature wax begonia rarely grows higher or wider than a foot, with densely rounded form. Flowers are small but abundant. Both leaves and stems are succulent and tender, with a waxy sheen. Propagation is remarkably easy by cuttings or division. Consistent watering is very important. Partial shade is tolerable, but if too shady, can inhibit bloom somewhat.

My neighbor describes sweet alyssum, Lobularia maritima, as a ‘polite’ weed. It naturalized over an area of her vegetable garden that was not in use at the time, but was easy to get rid of when the space was needed for something else. A few plants that were left in the perimeter bloom almost continuously and fill in other unused space between herbs and perennials without interfering with them.

As a bedding planting, sweet alyssum is most often planted from cell packs like most other annuals. Yet, seed is so easy to sow in bare spots among mixed annuals or perennials. Naturalized sweet alysssum sows seed so abundantly that new plants replace old plants before the old plants deteriorate.

Bloom is most often white, but can be shades of pink or purple. However, naturalized sweet alyssum eventually reverts to classic white. The minute, sweetly fragrant flowers form small, round clusters over the delicate mounds of finely textured and sometimes sparse foliage. The tiny leaves are only about an inch long and quite narrow. The largest naturalized plants are not often more than a foot tall.

Like several annual warm season bedding plants, oxeye daisy, Leucanthemum vulgare, is actually perennial. Also, some of the less extensively bred sorts disperse enough seed to naturalize and potentially become invasive. Increasingly popular modern varieties that are prudent with seed might not be true to type. Some might revert to more prolific forms.

Modern varieties should not get much higher than a foot and a half. They should also be more dense than the simple species, which gets a few feet tall. Foliage and form is quite variable among varieties. Stems are solitary or branched. They may be leafy or sparsely foliated above basal rosettes. Leaves might be lobed or serrate, with or without petioles.

The solitary, paired or tripled composite blooms of oxeye daisy are not so variable. They are classic daisies, with a dozen to three dozen clear white ray florets surrounding bright yellow disc florets. Without deadheading, fresh new bloom overwhelms deteriorating old bloom. Oxeye daisy is splendid as a cut flower. Spring bloom continues through summer, and can actually continue sporadically for as long as the weather is warm.