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Annual Plantings: Basic Care for Annuals - Apr 2, 2014

By: Lindsay Hendricks, Horticulturist, Green Bay Botanical Garden

Now that you have picked out your plants, you are probably wondering what is the best way to care for them. This blog will focus on the basics for caring for your annuals; stay tuned for more blogs on watering, fertilizing, mulching, and weeding.

 

Planting: Once you get your plants home you will want to get them in the ground as soon as possible. Before choosing a location, know if your plant prefers sun or shade, and wet or dry soil. Gently remove the plant from its pot, gently teasing the roots apart. This stimulates new root growth and will prevent the plant from becoming root bound, thus increasing its chances of finding nutrients and moisture during periods of drought. Make sure to plant the crown of your annual at the same depth it was in the container, to avoid crown rot and possible death of the plant.

 

Watering: After planting you will want to thoroughly water your annuals to settle the soil around the roots and rid the soil of air pockets. After the initial watering you will want to check for water regularly. Most annuals typically need about one inch of water per week, depending on weather conditions. It is best to water long and deep once or twice a week than to apply quick splashes of water every day. This method promotes deep root growth and will help plants survive periods of drought. When the dog days of summer arrive, you will need to check for water more frequently, especially with containerized plants. Keep an eye out for wilted plants, as this is usually an indicator they need to be watered. However, this can also be a sign of crown or root rot, but we will not get into that today.

 

Fertilizing: Annuals are heavy feeders, so a regular fertilization schedule is key to getting the most abundant blooms. Before planting, prep the soil with fertilizer—at the Garden we use a combination of 10-10-10 and Milorganite. After planting, fertilize with a quick-release, water-soluble fertilizer such as Miracle Grow every 7-14 days. Keep in mind that contrary to what the packaging claims, plants will absorb most of the nutrients through their roots in the soil, NOT from the foliage or flowers!

 

Mulching: Mulching the soil around your annuals helps retain soil moisture, regulate soil temperature, and best yet, acts as a weed barrier. You will want to use 2-3 inches of an organic mulch (i.e. not stone, plastic, or rubber) making sure to keep it away from the crown of the plant to avoid plant suffocation and rot.

 

Weeding: Weeds compete with your annuals for soil moisture, nutrients, growing space, and sunlight. Keeping up on weeding will increase the chances of your annuals surviving and thriving. If you are new to gardening, go online or to the library and check out a weed identification book. If you are a smartphone or iPad user, I am sure there is an App for that! Remember, the definition of a weed is a plant growing where it is not wanted: one person’s flower is another person’s weed and one person’s weed is another person’s flower.

 

Deadheading: Deadheading is the removal of spent or dead flowers, either to improve the appearance of the plant or to encourage more flowering. How does deadheading encourage more flowering? Well it’s pretty simple: the goal of annuals is to grow, set seed, then die. By removing potential seed heads the plant will continue to flower in hopes of producing more seeds and reproducing.

 

There are two ways to deadhead, depending on the type of plant. For shrubby plants with large flowers or tall stalks (zinnias, marigold, and salvia) cut off each flower individually with pruners and cut off enough of the stalk so it doesn’t awkwardly protrude from the plant. For shrubby plants with many small flowers (lobelia, alyssum, and ageratum), shear off the spent blooms with a grass shear being careful to avoid new buds.

 

For best results, deadhead regularly throughout the growing season. Ideally you would go out every day, but who has time for that? Dedicating a day or two a week should be sufficient to keep up on your garden. However, there may be some instances when you want to forgo deadheading. One example is if you want your annuals to reseed, such as annual snow-on-the-mountain (Euphorbia marginata), tall amaranth (Amaranthus caudatus), or tall verbena (Verbena bonariensis). Another example is if you want your plants to be a seed source for birds, such as sunflowers, annual varieties of hyssop (Agastache), or bachelor buttons (Centaurea cyanus). 

 

Pinching and Pruning: Pinching is done with your fingers, and is typically used on plant material that is succulent and small in diameter. Pruning requires the use of hand tools such as pruners or scissors and is typically used on plant material that is somewhat woody and larger in diameter.

 

Pinching and pruning can be used to deadhead flowers but also to manipulate the size and shape of your plant material. If young plants become tall and spindly, pinching or pruning back the tips of the plants will encourage branching and help your plants stay compact and bushy. Simply pinch the growing tips or flower buds back to a node (the point on the stem where buds, leaves, and branching twigs originate). Annuals that benefit from this method include basil, zinnia, coleus, and fuchsia.

 

When older plants become unruly, begin to outgrow their space, or flop over, you can prune back unwanted plant growth to keep the plant’s size in check, just make sure to cut back to a node. My favorite example of this type of pruning is with indeterminate tomatoes that tend to look more like trees than tomatoes towards the end of the season. If you want to take the ‘professional’ approach, go online or check out a book from the library on ‘proper’ tomato pruning techniques. Believe me when I say this can become very technical, but my methodology is pretty simple: If it grows outside of its cage or flops onto another plant, it gets cut off. Harsh I know, but it gets the job done. Pruning excess growth on any plant encourages energy to be put towards flowering and fruit production. If you have vines such as morning glories that tend to go wild, feel free to keep them in check by cutting off any plant material that has sprawled onto other plants or off their trellis. Remember you are the gardener and you are in control of your garden, so take advantage of it! The beauty of annuals is they need to be replaced every year anyways.

 

Staking and Caging: Speaking of unruly vines and tomatoes, as a gardener it is important to always have an ample supply of garden stakes and cages or grow rings to support your plants. These are especially important when we get those rainy, windy days that Wisconsin is notorious for. Garden stakes are typically used for plants that grow tall and get top heavy (sunflowers), are bushy and have large flower heads but tender stalks (dahlias), or plants that have tall flower spikes (delphiniums and tall snapdragons). Some plants are better suited for cages or grow rings since they grow big and bushy and have a tendency to flop open once they get to a certain size. Annuals that benefit from this method include zinnias, dahlias, tomatoes, and some pepper varieties.  Caging also keeps plant’s fruits off the ground minimizing rot. Other plants that require support are annual vines such as morning glories, sweet peas, and scarlet runner beans. These vines will require a trellis or netting so the tendrils have something to cling to as they climb to the sky. Forget this step and your garden will become a big, tangled mess!

 

So now that you know the basics of caring for your annuals, you can easily have the most beautiful yard on the block. Make sure to keep following the Garden’s blog-The Dig for upcoming posts including more detailed information on watering, fertilizing, mulching, and weeding. And hey, there might even be an App for that!

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