Proper mulch for your blueberries can spell the difference between abundant harvest and pitiful failure. Here in New Jersey we take our blueberries seriously! We harvest blueberries from mid-June to mid-August. There are not many places that can compare to the plump delicious blueberries we grow here in New Jersey. The reason I believe we have top tier blueberry bushes is due to the abundant pine trees located in the pine barren portion of our state. These pine trees litter the ground with pine needles enriching and acidifying the soil.
The fallen pine needles are the best mulch for blueberry bushes. If you want the healthiest blueberry bushes with the tastiest blueberry fruit; imitate the conditions of the pine barrens by mulching blueberries with pine needles.
Use the right type of mulch
Blueberry bushes tend to have shallow roots so mulching is especially important. Picking the right mulch will help keep the soil moist.
The type of mulch can affect the PH of the soil. Soil acidity plays a large roll in the health of a blueberry bush because they are acid-loving plants. Blueberries like a more acidic soil, with an ideal range of about 3.8-5.5. This is much more acidic then what you would want your vegetable gardens, which should be around 6.5 ph. A soil test is always a good idea to see where your soil is at. Mulch is a great way to lower your PH if you have a more alkaline soils. Pine needles is the best mulch to do that with, but I will go over some other mulch options as well.
You can also add fertilizer with an acidifier to your soil to help lower the ph. I like to use Hollytone from Espoma to accomplish this. I throw this down at the start of each the growing season.
Pine needles or pine straw
In my opinion pine needles are the best mulch to use. It is low in cost or even free to many that have pine trees. A single pine tree sheds enough pine needles in the fall to mulch many blueberry bushes. Pine needles will suppress weeds, keep the soil moist, and lower the Ph of the soil. Pine needles enrich the soil with organic matter as they decompose. Spread an even layer a 4-6 inches thick on the soil surface around the root zone of the plant. The root zone extends to the farthest reaching branches of the plant. Make sure your pine needles are loose, not packed down so water can penetrate easily.
Wood mulches are another good mulch that can usually be easily found for cheap or even free. Ask a local tree guy or visit your local garden center and they will most likely have wood chips. Wood chips will add organic matter to the soil as it decomposes and help with soil moisture. Blueberry roots prefer moist soil. Throwing down wood chips around blueberry bushes is also great for weed control. Layer wood chips a 4-5 inches thick around your berry bushes. Make sure to scrape away the chips a couple inches from the trunk of the bush. If the chips are pressed up against the trunk moisture will get trapped and can girdle the trunk eventually killing the blueberry plant.
The only downside to getting wood mulch from a tree guy or garden center is you don’t know exactly what the mulch is made from.
Pine bark mulch or nuggets
Another great mulch to use is pine bark nuggets. When picking up wood chips from a tree guy or garden center it’s usually impossible to tell what kind of wood you are getting. The wood could be mixed up with poison ivy for all you know. Most garden centers will carry pine bark mulch/nuggets so you know exactly what you are getting. As pine bark decomposes (although much slower than pine straw) it will lower the soil PH of the soil making it more acidic. If your soil has a low ph or is too alkaline you blueberries are not going to thrive. Adding pine bark mulch is a good idea to ensure you have the proper soil PH to grow blueberry bushes.
Like all mulches pine bark mulch is an excellent choice to keep weed growth to a minimum. If you don’t have access to pine needles, pine nuggets are a great alternative that hold up all season and you can find bags of them for sale at your local garden center.
If you have a yard to plant blueberry bushes you most likely have grass clippings. This could be the most cost effective organic mulch you have at your disposal. Like the other mulches i mentioned it will add organic materials to the soil keeping your soil healthy and weed free. You may need to reapply more often with this mulch because grass clipping tend to decompose fairly rapidly.
Hay or Straw
Hay or straw will also work as a mulch for your blueberries. Both do a great job of suppressing weeds and help with water retention. As the hay and straw decomposes it also adds nutrients to the soil feeding your blueberry bush. They do decompose quicker then other mulches so you will need to re apply more often than say wood mulch for example. Hay and straw also sometimes are contaminated with weed seeds, so you may be doing some extra weeding if you choose this mulch.
Especially in the fall you may find your self with an abundance of leaves. Leaves are another great choice for mulch because again they help enrich the soil as they decompose, and suppress weeds. Make sure the leaves aren’t too large or layered to thick however because this may actually block the water from penetrating the ground around your blueberries. If you have a way of shredding the leaves this would be an even better mulch.
Cardboard has become a popular option for mulch in the vegtable garden. I like the idea of cardboard to supress weeds, but not as a mulch for blueberries. The cardboard will make it difficult for water to penetrate the soil. It will also impede the flow of oxygen from getting into the soil killing many of the benifiical organism that are going to help your blueberry thrive. In short i would avoid cardboard as a mulch for your blueberries.
Other Mulches to avoid
Avoid synthetic mulches such as black plastic and landscape fabric. Although these do a great job at suppressing weeds they do not enrich the soil with organic matter like other natural mulches and do not help insulate the soils over the winter. Also avoid any wood mulches that contain dye like red or black mulch. This may be fine around your house but i would avoid using them around edible plants you plan on eating.
When to mulch
Your blueberry bushes should always have a layer of mulch around it no matter the time of year. Mulch will help keep the soil cool and moist in the summer and help insulate the roots from cold in the winter. The best time to mulch is in the fall to get your plants ready for the winter, but if you’re planting in the spring dont wait to fall to throw some mulch down.
Depending on what the mulch is looking like another time to freshen up mulch is in the spring. I will loosen up the old mulch with a hand tool before putting a fresh layer over the top. Make sure there is always a thick layer of mulch around your blueberries so weeds cannot take hold.
How much Mulch
Put a layer of 4-5″ of mulch around your blueberry plant. The layer of mulch should extend to the drip line of your blueberry plant. The drip line is the circumference around the farthest reaching branches of the plant. This is where the majority of the water will drip off the plant when it rains. The drip line is also where most of the feeder roots of the plant are located which is where the plants takes up most of the water and nutrients it needs. Make sure your mulch ring cover up to or even a little bit past the drip line of the plant.
Dont let weeds or grass grow up around your plant. Weeds and grass will soak up water and nutrients that your blueberry plant needs to thrive and produce fruit.
Having a heavy mulch layer over your plants will keep the soil temperature more constant over the winter, so your plant will be protected even under harsh winter conditions. It is usually not the cold that hurts blueberry plants but the temperature fluctuations. Mulch will keep the soil temperature from changing drastically over the winter.
Highbush Vs Lowbush
Highbush blueberries as you might guess grow much higher than lowbush blueberries. They can reach the height of 6′ or more. They tend to to have larger fruit and are quite an attractive shrub with white or pink flowers in the spring, blueberries late spring into summer, and finally finish with fiery red leaves in the fall. Low bush don’t grow much higher than your knee and produce smaller but sweeter berries.
Most home gardens will opt for highbush blueberries because they are easier to harvest from and grow bigger blueberries. They are more readily available for purchase at your local garden center. Some of my favorite highbush blueberry varieties that i have grown Jersey, Patriot, North Country and Blueray.
Planting and location
To get the biggest harvest of blueberries you must plant your blueberry in full sun with well drained soil. Don’t pick a boggy shady spot or yout blueberry bushes will not thrive.
1. Start by digging a hole 1.5 to 2 times as big as the rootball of the plant. Do not dig a whole deeper than the plants rootball. The top of the rootbal should be equal or even an inch or so up above the surrounding soil. This ensures water drains away and does not sit in the hole drowning your newly planted blueberry plant.
2. Back fill your hole with equal parts native soil (The soil already on the property) compost and peat moss. Either homemade or store bought compost will work. Blueberries like fertile soil rich in organic matter. Resist the urge to put all compost in the hole you dug with no native soil. By adding back some of the native soil the roots will venture out into the surrounding soil more easily.
I always throw in a few shovel full of peat moss into the hole when planting blueberry bushes. Peat moss keeps the soil ph on the more acidic side which is good for blueberries and will hold onto water keeping the soil moist. It is the best option for soil amendments when planting blueberries. Although blueberries do like moist soil make sure you pick a planting location with well-drained soil.
3. Add your mulch of choice. About 4-5″ thick around the plant. Make sure you pull the mulch a couple inches away from the trunk of the plant.
4. Water it in! This is the most important watering of the plants life. Make sure to water heavy the first go around. I like to turn my hose on 1/4 – 1/2 way, leave it at the base of the plant, and set a timer on my phone for 20-30 minutes. Heavy less frequent wateringas are better then many light waterings. When you water heavy the water gets down deep into the earth so the roots reach down deep as well. If you were to water lightly the water will stay closer to the surface, so the roots of the plant will do the same. If your plant just has surface roots its more likley to dry out durring a dry spell, so water like you mean it!
With proper care you too can grow plump delicious blueberries in your own backyard. Just remember to mulch!
Check out my other gardening posts like How Long Does it Take for Vegetables Seeds to Sprout