By Dean Nernberg
Many horticultural varieties of native plants have been developed in recent years. However, these varieties, which are commonly sold in nurseries and greenhouses, have been greatly selected or genetically altered. If you want pure native stock, it is best to seek information from local gardening or native plant groups to locate reputable sources of seed or plants. Digging up and removing plants from the wild can deplete their natural populations and, for some species in certain areas, it is illegal.
Adventurous types might want to consider growing wildflowers from seed. Some species grow quite easily with this method, which can produce a lot of plants for less money. The trade-off is that it takes at least two years for plants to develop and flower; for some species, it can take several years.
It is important to remember that plants grown from seeds usually stay very small the first year. During that first growing season, plants are putting most of their growth into roots, so they can withstand drought. If you get 25 to 50 mm (1 to 2 in.) of growth the first year, consider yourself lucky.
Most species can be seeded in the spring, summer or fall, and will grow at the first opportunity. However, some species may need to be planted in the fall, allowing seeds to over-winter in the ground. If these species are planted in the spring, they usually won’t germinate until the following spring. Other varieties, like spring-flowering prairie crocuses and three-flowered avens, should be seeded as soon as their seed has ripened and is ready to fall or blow away; these plants germinate very well at this time. If stored until fall or the following spring, some seeds might take a year or more to germinate.
Regardless of timing, it is important to control fast-growing weeds that can quickly shade and out-compete native seedlings. Pulling the weeds is an option; however, if they are large and well rooted, it might be best to simply clip them close to the ground level. Yanking out a well-established root might dislodge and kill the surrounding small native wildflowers you are trying to establish.
Serious native plant enthusiasts avoid ‘shake in a can’ or other commercially packaged wildflower mixes. In most cases, these seeds are not native to their region and quite weed-like in nature. In fact, most come from California or another U.S. state and usually don’t perform well. Many gardeners with visions of wildflower meadows dancing through their heads scatter these types of seeds expecting miracles; in most cases, they are simply left with weed infested yards.
This is 4 of 5 in A Guide to Gardening with Native Plants