Parks, Recreation & Leisure

Parks, Recreation & Leisure / Parks & Forestry

Landscaping Tips

Success With Annuals
The first visit to your local garden center is an unmistakable sign spring has arrived, especially when you set your eyes on the brilliant colors and choices found in the annuals section. It is easy for even an experienced gardener to get lost in a greenhouse filled with so many fabulous choices.

Now is the time of year everyone wants to know when annuals can be planted, how to plant and maintain them, which ones will perform best in a given location, and which plants to choose for the greatest seasonal impact. Knowing the answers and some pre-planning can make the selection process more enjoyable, save time and money, and create a beautiful eye-catching summer display.

It is tempting to plant annuals too early in the spring, as temperatures occasionally reach 70 degrees. The frost-free date for Central Ohio is actually May 15. However, it is generally safe to plant annuals by Mother’s Day.

If you simply can’t wait or want to get a better selection of the hard-to-find annuals, you can purchase them earlier and store them inside at night. A garage works well as a temporary measure, however many plants quickly become intolerant of this treatment, especially if they don’t make it outside during the warmer, daylight hours.

Many people try planting and then covering their annuals if frost is predicted. Anticipating the weather in this manner is risky. A common mistake is forgetting to remove the covers the next day. In the event of a warm sunny day, particularly where plastic is used, these young annuals will severely wilt or die.

Some cool season annuals and vegetables can be planted earlier and even prefer cooler weather. Pansy, snapdragon, ornamental and edible cabbage, broccoli, and lettuce can all be planted earlier and are usually available starting in March. Plants like geranium, marigold, impatiens, petunia, and vegetables like pepper, cucumber, melon, and tomato plants shouldn’t be planted until Mother’s Day.

It is best to rototill and loosen the soil if possible before planting. Annuals also benefit from an inch or more of compost and a pre-emergent herbicide/fertilizer mixed into the soil to control weeds and give them a boost. This helps roots grow into the soil, improves water retention, and allows for easy planting. Planting holes should be wider than the root system but not deeper. Mulch the planting bed no deeper than approximately one inch, and do not bury the stems.

Be prepared for greater maintenance responsibilities. Annual plantings should require only minimal watering in the spring, but once summer rolls around, in-ground plantings require a good soaking about once or twice a week and containers and hanging basket need water daily. An occasional water-soluble fertilizer application is helpful. Water and fertilize in the morning – this reduces stress on the plant and their susceptibility to acquire disease. Keep in mind that certain annuals, like marigolds and geraniums, require frequent dead heading to remain clean and promote new bloom.

A well thought out plan is also important for success with annuals. I recommend an overall landscape design to include a mix of trees, shrubs, and perennials, with limited space set aside for annuals each year. A well-designed professional landscape plan should include these elements and have them properly labeled. Annuals are useful filler where you have temporary gaps in your landscape, you need a little added color, or want to highlight a space with a mass of summer bloom.

Determine whether the area will be sunny or shady and plant appropriately. Also, decide how many annual flats you need before you shop. Measure the length and width of the area, multiply those numbers together, for the total square footage. Then, take that number and divide it by the plant spacing to reach the number of plants needed for the given area.

Plan for an approximate color scheme based on your preferences and the bloom color of existing plantings. Try to stick to two or three colors that repeat throughout your garden, unifying your entire landscape. Also, consider the mature height you wish to achieve. It’s easy to give dimension to a garden by offering increasing height levels from front to back.

A good color and height combination for a typical sunny border could be pink wax begonia in front with taller Victoria blue salvia in the back. It is also an excellent idea to incorporate texture by mixing unique foliage plants with colorful blooming plants. Red verbena grown in front of phormium (a non-hardy foliage plant) planted either in the ground or in a container offers nice textural appeal. There are many excellent gardening resources available about annuals at bookstores or your local Upper Arlington Library branch.

By developing a preliminary plan based on these tips before heading to the garden center, you will enjoy assured success with your annuals this year.

Parks & Forestry Division
Parks & Recreation Department
City of Upper Arlington
3600 Tremont Road
Upper Arlington, OH 43221
Phone: 614-583-5340