Which makes a better ornamental garden — perennials or annuals? That is a matter of opinion and proponents and opponents of either side have valid reasons for their points of view. Each has its advantages and disadvantages.
Annuals have their advantages. Most of the annuals we choose are lavish in their color show.
If you have problems with perennial weeds, you can pull out the annuals at the end of the season and rework the soil to improve it, and you can work on controlling perennial weeds without damaging desirable garden plants.
Annual plants offer quick color and they tend to be splashy and lavish. Once they start blooming, many of our favorite annuals continue through the rest of the season. They must complete their entire life cycle from germination to blossom to seed production in one growing season. It is dictated by their genetics. If they require a longer season than Tooele County offers, or if we are impatient to have instant color, we have the option of starting them indoors several weeks before planting so that in the garden they will reach the blossoming stage earlier.
They also lend themselves to changes. If you didn’t like what you had last year, change it totally this year.
Last year’s focus may have been on shades of lavender and white petunias in a flower bed, but you always have a clean slate to go to shades of red, white and blue or gold and red using an array of different plants during the upcoming year. If you have a serious problem with perennial weeds, annuals are a good bet. You can completely clean out the bed in the fall and spray easily to control weeds before you start over to plant.
Annuals require work each year in preparing beds and planting the flowers. If you purchase plants to transplant, there is a cost factor to be considered. The plants are less expensive initially than most purchased perennials, but the cost reoccurs each year.
Perennials don’t need to be replanted every year. They may be expensive initially, but provided they are hardy, you don’t need to spend money to replace them each year.
With some exceptions, perennials only bloom for a short period. This can be an advantage or a disadvantage. Short bloom times can provide for change throughout the season. If a gardener designs the bed taking into account the time and period of bloom, then something can be in bloom all season. The beds will be interesting as they continually change. Perennials can provide variety throughout the season. If you plan and plant well, as one set of blossoms decline on one plant another will begin to put out flowers of perhaps an entirely different hue, size and shape.
Perennials benefit from digging and dividing. They can provide a source of free plant matter to share or move to fill in another area.
Not many perennials bloom all season long. Many of them have a short bloom season and then just sit there and grow or die back until the next season. If there is not another plant ready to come up as one goes down, the show is over.
Those who think that growing perennials requires less work than annuals since they don’t need to be replanted every spring or pulled out in the fall haven’t had much experience with perennials. They can require more work in deadheading, digging and dividing.
Although this does provide more free plant material as mentioned under advantages, it does require work and the plant may be difficult to lift in hard soils. Very aggressive perennials may become weedy. Very strong, vigorous varieties must be controlled so they don’t overwhelm their less aggressive partners. Weed control takes on a different face among perennials.
Difficult perennial weeds are much more difficult to control under and around permanent plantings. If you use chemical controls, you must be careful to protect the perennial plants from the damage that drift from weed sprays can inflict. Even annual weeds can be a problem. You cannot work the soil thoroughly with the plants in place so it tends to get hard and weeds are more difficult to pull. Weeds also grow up through perennial clumps or intertwine with their roots and seeds dropped into these areas are hard to control.
Mixing annuals and perennials
There is something to be said for mixing annuals with perennials to create a highly varied landscape. Many gardens are replete with a mixture of the two.
If you have perennial plants, you will have certain challenges to face. Keeping the weeds out can be difficult since they may be intertwined with the roots of the plants and grow up through them. Eventually perennials become overgrown and may need to be renewed.