plant line
Flowering Annuals
Martha Maletta, Home Horticultural Consultant
Dated -  January 12, 2005

It’s the main reason I grow my own annual flower garden transplants: trying new varieties. Every year is an experiment and last year’s was larger than usual. And, as usual, there were some successes and some “flops”.Flowering annuals (including tender perennials) have taken a back seat to hardy perennials among serious gardeners for many years. I’m not sure why, because, especially for the small or container garden, annuals provide season-long color, a challenge to achieve with flowering perennials. A very good reference on this large and diverse group of flowering plants is Armitage’s Manual of Annuals, Biennials and Half-Hardy Perennials by Allan M. Armitage, 2001, Timber Press.

Fortunately, the bedding plant industry seems to be moving beyond petunias and impatiens. And the catalogs, particularly some specialty ones, offer hundreds of selections. Starting plants from seed provides a chance to try new or different varieties of common annuals as well as unusual ones.

I grew my first petunia from seed because I wanted to try one of the Tidal Wave series, a spreading/trailing multiflora cultivar. It was an astounding success in containers, almost too vigorous for the smaller ones. It bloomed prolifically in sun and partial shade, held up well to the rain we had plenty of last year and never needed deadheading, the bane for me of growing the larger-flowered petunia cultivars.

Another “trailer” was almost too successful for my small annuals-only bed. Nasturtium ‘Indian Cress’ was slow to bloom, producing a large mound of leaves early in the summer. But, once it shifted to rambling mode, the yellow, orange and red flowers highlighted the late summer and fall display with the plant aggressively filling in spaces where some other varieties were starting to peter out. It would be a great plant for a large area, and ,I assume, it could be trellised.If I figure out how to manage it, Browallia americana ‘Sky Blue’ could well become a regular in my gardens. It should make a great filler plant, the clouds of small violet blue and white flowers softening or blending larger plants. It bloomed abundantly, even in partial shade, all summer. However, it was quite brittle, larger and taller stems breaking from rain. I’ll try pinching it early to promote low branching and control height.Rudbeckia hirta ‘Prairie Sun’ was a real winner, the best annual rudbeckia I’ve tried. Sturdy plants supported very long-lasting blossoms, many subtly bi-colored gold and orange. Their green centers complemented the lime-green nicotiana that has become a staple of my gardens. Some other “successes”. Coleus ‘Limelight’, a non-variegated cultivar, provided just the highlight my partial-shade herbaceous green border needed.

Pentas ‘New Look Pink’ was very slow growing and coming into flower, but it was attractive and produced its clusters of star shaped blossoms until frost. This might be one to purchase as a plant rather than grow from seed. I really liked blue woodruff (Asperula orientalis), a delicate plant that should be viewed at close range. Contrary to the literature, it was ephemeral in my garden, finished by mid-July. I’ll try to find the best use for it.

As for 2004’s “flops”:

Zinnia ‘Red Spider’ (Z. tenuiflora) – the flower form and color and plant habit were extremely variable and the flowers made too little impact. Salvia coccinea ‘Dwarf Hummingbird’ – vigorous plants, and flowers did, in fact, attract hummingbirds, but flower production and color were by far best in cooler weather.
Gentian sage (Salvia patens) – eye-stopping deep blue color and unusual flower form, but sparse flower production makes this plant better for mass planting.
Dichondra ‘Silver Falls’ – delicate plant with bright silver foliage, tried as a trailing plant in containers, but extremely slow growing.I found some “keepers” in 2004 to add to the already long list of “keepers” from past years…. I think I need more garden space!