If your plants look otherwise healthy, check for other problems first. If they show signs of malaise or stress, check all the growing conditions. Is the plant getting plenty of sun and water? Are there any signs of disease or pests? How do the other nearby plants look? Have you had your soil tested recently? If your soil pH isn’t in a good range, it won’t matter how much fertilizer you add; your plants won’t be able to access it. All these factors work in combination. It helps to know something about the type of flower you are growing:
Annuals should flower their first year, but it can still take several months for them to mature. You may not see flowers until mid to late summer. Biennials, like hollyhocks, do not usually bloom at all their first year and then fade away shortly after flowering in their second season. Perennials are being bred to flower more quickly. If you are buying large plants, they should be plenty old enough to start blooming the first year you plant them. Even flowering trees and shrubs are being designed with the impatient gardener in mind. But there are still plenty of old-fashioned varieties out there that need to settle in before they hit their stride. Once they do, they should become reliable bloomers.
Temperature also plays a role in flowering. The warmth of the sun is often what is needed for a flower to open, so the time of day the sun shines on your flower garden also plays a role. Morning light is cooler. Plants with an eastern exposure may be getting only morning sun. Flowers that require “full sun” will bloom more in a western exposure, where they get the hotter afternoon rays. Of course, there are plants that will wilt or fry in the hot afternoon sun, so learn what your plant likes. Flowers that need a period of cold to set their flowers buds or to break dormancy, such as spring bulbs and peonies, won’t get what they need if the winter is too warm. This can also cause some plants to come out of dormancy early, only to be killed back by a late spring frost or snowstorm. Too cold, not cold enough, too wet, or too dry? There’s really not much we can do about this other than looking for varieties that are well-suited to our area. Even then, there will be seasons when we will just have to roll with the punches.