Annuals, Perennials, and Biennials

ANNUALS, PERENNIALS AND BIENNIALS....yea ....there are different types of plants....and some are not for me, what they are for you! I thought maybe I would address this today, as I have been asked a few times to tell the difference between them.

There are literally hundreds of plants available to choose to plant in our gardens. Some of these plants are admired for their foliage, some for their shape, and some for their colorful blooms. One of three categories can define all all plants. Annual, Perennial or biennial.
What do these terms mean? How do you choose which one you want? What is the difference? Can they be planted amongst each other?
An annual is a plant that has a short life span. This life span is usually only one season or a few months long. These types of plants are considered temporary and are disposed of once their season is over. Should you plant annuals in your garden, you will have to plant them ANNUALLY. In my area, an annual is planted in early spring once the threat of frost has passed and is pulled and discarded once the killing frosts of fall have pulled it past its prime. Some examples of annuals from my gardens would include such plants as Marigolds, Petunias, Alyssum, Lobelia and Dusty Miller. The plants considered annuals in my zone may not be the same as those in your area…check with your local garden center or research your zone. Each climate has different conditions and such plants may differ in each region.
A perennial is a plant that lives much longer than an annual. This type of plant will live for several years or more. In a colder climate, a perennial will “die off” for the winter months. This means that the leaves and some of the top growth will appear to die, when in fact the roots are just resting for these cool months and getting ready for the warm weather to return. Once spring arrives, the plant will rejuvenate and new growth will appear. In some cases, you will need to cut the entire top of the plant down to a few inches above the soil, and the plant will start fresh. (Clematis for example) Other perennials will lose their leaves, but once the spring arrives, they will resume or pick up where they left off in the fall producing new growth on “old wood”. (Hardy Hydrangea or other shrubs).
There are a couple of things to keep in mind when purchasing a perennial plant. Hardiness, growth habits, and required conditions are very critical factors to consider when planning for a perennial planting. By not considering these things before you plant your garden, you may be setting yourself up for more work or disaster.
Hardiness is the term used to describe the climate conditions that each plant can tolerate. A plant considered hardy, is capable of surviving in unfavorable conditions. Cold weather, poor soil, deep shade or lack of moisture are examples of unfavorable conditions. Hardy plants are the toughest of the tough. The hardier the plant the better the chances of survival it will have.
Growth habit is a term used to describe the way a plant will perform in your garden. This includes how fast a plant will grow. Some are very fast to mature and others are very slow. Growth habit will also describe the “way” a plant will grow. How tall, or the girth of the plant is a habit. The type of leaves a plant produces is also a type of growth habit. Some plants are evergreen and some are deciduous. Evergreen plants have needles such as pine or spruce varieties of shrubs or trees. Deciduous plants grow leave and may lose them in the “off” season. Some plants will become round balls and will spread and increase uniformly on an annual basis. Others will require shaping and pruning by the gardener. Others still, will become very tall or bushy, or both. Not paying attention to the growth habit of a plant can ruin the overall performance or appearance of your garden plantings. Planting a perennial that will perform to a large bush in the front of a bed or area, will obstruct the view of the plants behind and around them and could possibly cause the others nearby to perish.
Special requirements are very important to realize before planting many perennials. Some plants require lots of light to flourish, while others prefer some shade. Some plants like lots of moisture, while others will tolerate some dry conditions. Soil conditions are often an issue as well. Such plants as Hydrangea will flourish in a slightly more acidic soil, while others do not have much of a preference. Keep this in mind when you purchase your perennials. The local garden center will have plants for the conditions of your climate and soil type on hand, but sometimes they will have a few that will be a little more “tender” and could require special measures be taken in order to survive.
Biennials are plants that will grow leaves the first year of life, fall dormant for the winter or “off” season, and then bloom the second year before dying. They re-appear in your garden by self-seeding. Examples of biennial plants in a garden are Hollyhocks or foxgloves. This type of plant is considered as semi-permanent, where an annual is temporary and a perennial is permanent. Biennials can raise potential problems due to the habit of self-seeding that they have. Your garden could easily be overrun with one particular species of biennial plant should you not keep up with the removal of seedpods before they reach maturity, or the thinning of germinating seed.
In your garden, it is possible to combine all of the types of plants to create a beautiful display. Taking into consideration all the habits and requirements of each plant prior to planting is important. If you plant some young perennials, and need to fill the space between them, annuals are an excellent choice, as they are temporary and are replaceable annually to suit your needs.