Mulch protects the flower garden during the winter, keeps the soil cool and moister during the summer, deters weeds, slows erosion and reduces soil compaction.
Mulching flowers also improves the soil and replenishes organic matter on an ongoing basis. Correct mulching is very important to success with the flower garden.
What Kind of Mulch to Use for Flowers
You can use virtually any organic material as mulch. Availability and price determine which mulch is best. Your choices include mulches you might be able to collect on your own property and those that can be purchased.
At home, you might have a ready supply of (herbicide free) grass clippings, chopped autumn leaves or pine needles along with half finished compost.
Mulch can be purchased either packaged in bags or in bulk by the cubic yard or scoop. Pine bark fines and nuggets, double shredded hardwood bark, and pine straw are common examples. Less common mulches such as cocoa bean hulls or licorice root may also be available depending on where you live.
How Deep Should Mulch Be in Flower Bed?
Maintain a layer of mulch about two to three inches thick year round. Thicker mulch might seem like a good idea, but it is really not. If too deep, mulch prevents air from reaching the soil and plant roots and may prevent rain from reaching the soil, especially if the mulch has compacted. Two to three inches is enough to help keep the soil cool and moist during summer, buffer temperature changes in fall and spring and help insulate the roots in winter. This is also deep enough to deter weeds.
Why You Should Rake or Fluff Mulch
Organic mulch packs down over time and needs periodic raking. This helps it hold air and insulate better; it also dislodges any weed seedlings. Some mulches fade over time after exposure to the elements; raking neatens and refreshes the appearance as well.
Mulch Rots Away: Adding More Mulch
Eventually, you will need to top up or replenish the mulch to replace what has rotted down and decomposed. Simply add more fresh mulch on top of the existing mulch. It is fine to mix mulches. Using a variety of materials supplies a wider variety of nutrients to the soil over time.
When you mulch, keep a space of an inch or two between the stem(s) of the plant and the mulch. This gap assures air circulation and discourages pests from hiding there.
Some plants spread out along the ground. Lift up the branches and insert mulch below them, or simply mulch around the perimeter of the plant. Do not place mulch over the crown or atop the plant — this can smother the plant and encourage disease.
Fertilizing Mulched Flowers
If you fertilize your flowers with a granular fertilizer, pull aside the mulch and spread the fertilizer over the root zone, then replace the mulch. Or, broadcast the granules over top of the mulch and rake lightly.
Winter Mulch for Flowers
Where winters are severely cold, prepare by mulching the flower bed deeper (four to six inches) in late fall. Next spring, pull aside the mulch so the sun can warm the soil.
Some gardeners also mulch over top of their flower plants in mid winter to help protect the crowns during the time when temperatures are low – especially if there is no snow. Use a non-packing material to hold an insulating blanket of air over the plants. For example, use evergreen boughs – these can be branches cut off the decorative Christmas trees and recycled after the holiday. Straw and fluffy oak leaves can also be used but take care they do not compact and become a soggy wet, smothering layer over the plants. Remove in early spring to allow the sun and air to reach the plants once again.
Benefits of Mulching the Flower Bed
Mulch offers many benefits for the flower garden, especially improving and protecting the soil. It helps you save work by weeding less and cuts back on watering, too. Every flower garden should be well mulched all year long.