By Kathy Torres
While you still have a little time to prepare for the growing season ahead, it’s a good idea to create a plan for fertilizing your plants and to stock up on the supplies you need. The chores are numerous in the spring, so be ready when the conditions are right. By following an established schedule for fertilizing, you are providing the best care for your plants, giving them the nutrients needed to flourish, at a time that is most advantageous. When it comes to fertilizing, there’s not a “one size fits all” however, with a little guidance on products and proper application, you’ll see it’s not too complicated.
To start… it’s good to have a basic understanding of the science of fertilizers, and to know that all plants have different needs and all fertilizers are not the same. Available in synthetic and organic forms, most plant fertilizers are created to address those specific needs. A key message on the packaging or label of a fertilizer blend is the N-P-K content, which indicates the ratio of 3 critical nutrients by weight: (1) nitrogen, (2) phosphorus and (3) potassium (standardized in this order). These are necessary for healthy plants and not often available in sufficient quantities in the soil. Each has a particular effect:
- Nitrogen (N) is necessary for leaf health and makes plants greener.
- Phosphorous (P) promotes root growth and increases bloom and fruit production.
- Potassium (K) helps plants fight disease and remain vigorous in extreme temperatures. Note that potassium is usually provided in the form of potash, also known as K2O.
The N-P-K numbers represent the percentage of the weight of the bag that is attributable to each component. To understand what you’re getting in a bag of fertilizer, here’s a simple example: a 100-pound bag of 10-10-10 (basic, all-purpose) contains ten pounds each of nitrogen, phosphorus, and potassium. The rest is filler, which gives it bulk and makes it easier to spread. As you become familiar with different fertilizers, you will notice many specialized blends, such as 19-8-10, for plants needing more nitrogen, or 9-15-13, for plants needing more phosphorous. Because there is usually more potassium found naturally in the soil, it’s not likely to find an N-P-K with the highest number being potassium, however, more is typically needed.
Existing ornamental shrubs and trees in your landscape, whether evergreen or deciduous (drops leaves in fall/winter), should be fertilized in spring when new growth appears, usually in mid to late March. A late frost or freeze can throw things off by damaging the tender new growth, so if the forecast looks wintery, wait a bit longer to apply fertilizer. For most plants in this category, one spring application is sufficient, although some varieties are heavy feeders and require additional applications. If you have mature trees and shrubs, especially if they are grown in good soil, they may not need any fertilizer at all.
Timing and application varies for fertilizing these shrubs and trees:
SHRUBS | WHEN TO APPLY |
---|---|
Azaleas, Camellias, Gardenias | Early spring (Mid-March) & after blooming |
Hydrangeas | March, May & July |
Hollies, Rhododendrons | Early spring (Mid-March) & after blooming |
Roses | After pruning (Early Feb) |
TREES | |
Citrus | Spring, (March) summer (June) & fall (October) at 90 day intervals |
Fruit | Early spring (March) when branch tips show green |
Palms | April & June |
Pecans | February & June |
Mark your calendar for February to fertilize roses (prune first) and pecan trees. This is the official starting point for the year. In Mid-March (temperatures permitting) it is time to get busy on ornamental shrubs and trees, then, as indicated above for the “special” ones. Be sure to mark the calendar for those plants that will need additional applications. These require a little extra and/or a blend that will meet specific needs, such as soil acidity.
Speaking of soil acidity, it’s a good idea every 3 or 4 years to have your soil tested so you will know the pH and if soil amendments are needed. Having proper pH can affect how well the plants will grow in the soil and will impact the effectiveness of fertilizers. Wingard’s can provide assistance in coordinating soil sampling and testing with Clemson Extension Service in Lexington. Just ask staff at the checkout for details.
Typically, fertilizer is applied at the dripline of a tree or shrub and care should be taken to avoid getting too close to the trunk(s). For more columnar or narrow plants, applying a little further out than the dripline is more desirable. For more information on this, as well as general information on fertilizing shrubs and trees, click HERE to access Clemson’s Fact Sheet on this topic.
It is not necessary to fertilize NEW plantings of shrubs and trees right away, however, Bio-Tone Starter (composed of micronutrients… bacteria, humates & mycorrhizae) is recommended to increase root mass and help avoid transplant loss. If you plant in the spring, wait 6-8 weeks to apply fertilizer; if you plant in the fall, wait until the following spring.
Annuals and Perennials add an abundance of color and interest in the landscape and are plentiful at Wingard’s in spring and summer. Because the growing period for these beauties is in the warm to extremely hot time of year, they need a bit more help to stay healthy and to put on their best show. Make sure you have good, rich potting soil and fertilize from time of planting throughout the season according to label directions. Choose a slow-release fertilizer that works for 3 or 6 months or a 30-day fertilizer. Add these fertilizers to the top of the soil after planting and gently work the granules into the top layer of the soil. For maximum results, add a water-soluble weekly fertilizer for a little extra boost. An IMPORTANT TIP (hinted at this earlier) for purchasing fertilizers for these big bloomers is to look for a high middle number in the N-P-K.
The folks at Wingard’s have put together a flyer with the timing guidelines mentioned above for applying fertilizer, along with product recommendations readily available in the garden center. Click HERE to access the flyer.
When using any fertilizer, ALWAYS…
- Read and follow instructions on the container or label.
- Avoid adding more than indicated or you may cause damage to the plant.
- Water-in fertilizer when applied, otherwise the plant(s) will not absorb it.
- Store in a protected area that will not get wet.
Margaret Atwood, a Canadian novelist and poet, has a quote that really sums it all up for me. “In the spring, at the end of the day, you should smell like dirt!” Spring is just around the corner and I must admit, I am excited about getting my hands dirty, seeing the grass turn green, buds forming on my yellow rose bush, new growth flushing out of the ground that will host beautiful day lilies and bare hardwoods becoming bright green with new foliage. Yes, there is work that comes with it, like raking all the leaves out of the beds, picking up branches and sticks, and removing last year’s dead roots from all the pots. And then… fertilizing. Maintenance is not my favorite gardening task, but I know it is necessary to keep plants growing, thriving and looking good. In gardening, it is pretty much ongoing. After everything is planted and fertilized, there is watering, deadheading, looking out for pests, and weeding. But, between the chores are the moments when the sun is shining and the temperature is getting warmer, birds are singing and rushing to and from the feeders, the buds are opening for bright, colorful blooms, and the joy of the garden is upon you. Happy spring…Enjoy!