Definition - What does Hardy Annual mean?
The terms “hardy” and “annual” might seem mutually exclusive, but they are not. A hardy annual is just a plant that only lives for a single year, but is hardy enough to hold up to exposure to frost.
MaximumYield explains Hardy Annual
An annual is a plant that only lives for a single growing season. Thus, they are not generally thought of as being hardy. However, hardy annuals do exist, and they can provide many benefits to the outdoor gardener. A hardy annual is nothing more than a plant that will only live for a single growing season, but that can withstand wintertime temperatures and possibly frost.
Hardy annuals begin life as a seed, germinate and grow into an adult plant, and then produce seeds before dying at the end of the season. However, because they are tolerant to the cold, they can be planted well before other plants can, which would be damaged or killed. For instance, snapdragons can be planted in the fall or early spring, giving gardeners a head start without having to worry that the plants will sustain damage from cold temperatures.
You will also find that hardy annuals can make do in poorer soil and harsher growing conditions than many other plants. This is often because they were originally adapted to semi-arid growing conditions, or evolved to deal with soil that lacked many nutrients. However, while they will grow in poor soil, it is recommended that they receive a mild fertilizer (7-7-7) to help support growth and the development of strong stems and vibrant flowers.
Finally, understand that hardy annuals and half-hardy annuals are not the same thing. Half-hardy seeds cannot be planted before the last frost, but can be sown before cold temperatures are gone for the year.