It is officially spring, which is a good time to freshen up the mulch in your landscape. Mulching your garden beds has many benefits, including:
- Moderating the temperature of the root zone. Mulch provides an insulation effect, keeping the soil warmer during the winter and cooler during the summer.
- Encouraging the conservation of moisture in the soil by reducing surface evaporation.
- Helping control weeds. A two-inch layer of mulch reduces the germination and growth of weeds.
- Preventing the soil from crusting over, allowing water to penetrate and percolate. Mulch can improve soil aeration, soil structure (less soil compaction) and drainage.
- Adding organic matter to the soil, improving fertility.
- Restraining soil erosion, especially raindrop erosion.
- Reducing the chance of mechanical injury to trees and shrubs from lawn mowers and weed trimmers.
- Giving the landscape a more pleasing, manicured appearance.
If you are sold on the benefits of mulch, the next concern is choosing the best mulch for your yard. There are two types: Organic and inorganic. The organic types are decaying plant materials, which add organic matter to the soil and improve fertility. As they break down they require replenishment. Common organic mulches include, compost, shredded leaves, pine straw, shredded hardwood, bark, etc. Fresh organic material that has not been composted or aged (sawdust, wood shavings and unaged wood chips), consume large amounts of nitrogen as they break down, robbing plants of this vital nutrient, stressing them and making them prone to disease and insect damage.
Inorganic mulch includes plastic sheeting, geotextiles, stone, gravel and shredded rubber. Inorganic mulches do not break down and therefore do not improve soil fertility. Inorganic mulches can make future planting more difficult.
In the home garden mulch provides a finishing touch to the garden, and personal aesthetics often determine the kind of mulch to be used.
- Pine needles/pine straw: Lightweight and easy to spread, organic, slow to deteriorate, tends to stay put on slopes and in heavy rain, resists compaction and does not track into the home on shoes.
- Pine bark nuggets: Available in multiple sizes, lightweight and easy to apply, slow to deteriorate, resist compaction and tend to wash off slopes and float away in heavy rain.
- Shredded hardwood: Heavier than the prior options especially when wet. Slow to deteriorate, tends not to wash and can compact over time. Available in colors.
- Compost: Contributes large amounts of organic material to the soil quickly, improving soil structure and nutrient and water holding capacity. However, it do not inhibit weed growth nearly as well as wood or needle mulches.
- Shredded rubber: Does not breakdown. The color remains stable for many years and it stays put better than almost any other mulch. It is very heavy and difficult to move, adds no beneficial organic material to the soil and is costly.
- Plastic: Although it is an excellent weed barrier it should not be used as it prevents rain from reaching the soil and cuts off oxygen to plant roots.
- Landscape fabric and geotextiles: These are often used for weed suppression and are then covered with mulch for aesthetics. As the mulch breaks down it becomes soil that will support weed growth. These weeds are difficult to remove if their roots have grown through the fabric. An inorganic mulch on top of this fabric is a better choice.
A light two-inch layer of mulch is all you need. Too much mulch will do more harm than good, so don’t be overly generous. Remember not to pile mulch around the trunks of your trees and shrubs; you should pull back the mulch from the base so no mulch touches the bark. If you pile mulch onto the bark, it is exposed to dark and moisture. Bark will begin to rot, allowing for attack by insects and diseases. Roots will grow up into the mulch, which can encircle the trunk and choke off the tree’s main roots. Volcano mulching will result in the slow death of your tree.
In addition to mulching, there are additional reasons to get out into the garden this month.
Gardening activities for April
- Plant: Roses (no later than April 15). Buy azaleas while in bloom so you can see the color. After April 15, plant annuals and warm-weather vegetables, caladiums and container plants. You can direct-seed easy-to-grow flowering annuals and vegetables. Some easy flowers to grow from seed include marigold, zinnia, sunflowers and cosmos. Beans, peas, corn and okra are some easy direct-sow vegetables, while dill, basil and cilantro are some easy direct-sow herbs.
- Lawn care: Spot control weeds with herbicides. Overseed any thin fescue lawn by the end of the month.
- Fertilize: Spring blooming shrubs after blooming.
- Prune: Flowering shrubs as soon as they finish blooming. Cut back any woody perennials that may need it, such as rosemary, rue, lavender, Santolina and Artemisia after the danger of frost has passed (April 15); if done earlier new growth may appear, and a freeze can kill that new growth and sometimes the entire plant.
- Other: Inspect plants for insect damage and fungal disease and treat as needed. Late in month move houseplants outside.
- April is the month for plant sales here in the Mid-South. You can learn about what grows well here, get tips from knowledgeable gardeners and purchase plants you won’t find at box stores by attending one of these sales:
- Memphis Botanic Garden Spring Plant Sale: 9 a.m.-5 p.m. April 12-13
- Dixon Gallery & Gardens: 9 a.m.-4 p.m. April 12 and 9 a.m.-2 p.m. April 13
- Bartlett City Beautiful Plant Sale: 9 a.m.-6 p.m. April 26-27 and noon-4 p.m. April 28
- Lichterman Nature Center: 9 a.m.-5 p.m. May 3 and 9 a.m.-4 p.m. May 4
TOM RIEMAN of Bartlett is a Shelby County Extension Master Gardener and secretary of the Bartlett City Beautiful Commission. Keep Bartlett Beautiful is among the activities of this commission. Contact him at thrieman@aol.com.
