Over the past few weeks we've talked about garden design, particularly choosing the site for the garden based on light availability and drainage and putting in the hardscaping, which includes walkways, arbors and other structures. Now we can start thinking about plants.
Most plants need three things to thrive: light, water and soil. I say most plants because there are plants - typically tropical plants that we can only use as houseplants - that can survive just fine without one or more of these things, but we aren't going to talk about them.
Probably the main goal of every person who dreamed of a flowering landscape was to have something blooming at all times throughout the season. This is great if all you plant are annuals, also known as ''bedding plants.'' The most common annuals start to show up at the garden centers and big box stores as early as April.
These are plants such as petunia, marigold, salvia, snapdragon and many others. Annuals are usually bright, bushy and prolific bloomers that love lots of sunlight and come in a wide variety of colors.
Most of the gardeners I know love annuals, although they don't use them as the primary plants in their gardens. Instead they are used as fillers because no matter how hard we try, there is always a period of time during the season when nothing seems to be in bloom. This is because perennials, which are most gardeners first choice when it comes to plants, usually only bloom once or twice in a season.
Annuals are what we call flowers that only live for one growing season. Their job is to flower and make seeds so their species continues and to do it quickly. Some annuals may fool us into thinking they are perennials by dropping their seeds to the ground and although the plants can't live through our winters, the seeds can and will grow the next season in what seems to be the same place they grew the prior year. Some of these reseeding annuals include Malva zebrina (also known as marshmallow), cleome, cosmo, morning glory, nicotiana (four-o-clock), rudbeckia (black eyed Susan), and verbena (Sweet William). There are more, but these are a few examples.
The challenge for any perennial gardener is to have something in bloom all season, but this is not an easy task. Several things can contribute to the blooming habits of plants, including the amount of light they receive, the weather conditions and even the condition of the soil. For most gardeners it can be trial and error and nothing ever lasts, including perennials. Don't let the term "perennial" fool you. Most will live five years or more, but there are short-lived perennials that don't stick around as long.
A perennial is a plant that can withstand our winters and will return the following season, but the trade-off with these plants is that they usually only bloom once during the season. Some perennials bloom more often, such as damask rose, and some varieties of bearded iris and threadleaf coreopsis. To get these plants to rebloom, a little maintenance may be required, such as cutting them back immediately after their first blooming period to encourage new growth and a second bloom later in the season. Damask rose will put out a flush of bloom in spring and then will rebloom, although sparsely, the rest of the season.
Don't try to judge a plant's blooming time by whether it is blooming in the garden center. Commercial plants are propagated in greenhouses, fed growth hormones and raised under conditions that fool the plant into thinking it is time to bloom. This is to make it attractive to the buyer, but that doesn't mean if you plant it in your yard it will bloom again at the same time next year.
The best way to determine when a plant will bloom is by planting it and watching. Keep records noting the date it bloomed and watch for the same trend the following season. There are early, mid- and late-blooming plants that make it easier to experiment and we'll talk about those in upcoming weeks.