Boxwoods need healthy soil and adequate pH to thrive. If the pH is too low or too high, it’ll experience severe growth problems. Furthermore, there’s a good chance that the leaves will look dry, dull, and wilted. Once you know what kind of soil your boxwood needs, you can grow, propagate, and maintain it much easier.
Boxwoods aren’t acid-loving plants because they require a relatively neutral pH of 6.5 to 7.5 for optimal growth. If the soil is too acidic, it’ll burn the roots and make it almost impossible for the plant to grow healthily. Make sure you use a neutral pH fertilizer for your boxwoods.
In this article, you’ll discover what kind of soil and fertilizer your boxwoods need, how you can adjust the soil’s pH, and what happens if the soil has a poor pH.
Do Boxwoods Need Acidic Fertilizer?
Boxwoods don’t need acidic fertilizer because it can damage their roots. Instead, opt for neutral, all-purpose fertilizer. You can also use topsoil, compost, or mulch to fertilize your boxwoods if they have all of the nutrients, carbon, and nitrogen the plants require.
A lot of experts recommend using a fertilizer with a pH of around 6.5 to ensure the soil doesn’t get too alkaline or acidic (source).
Stick to all-natural fertilizers to keep unwanted harsh chemicals out of the dirt. You can also aerate the soil after watering it to make use of the water’s neutral pH.
Try Burpee All-Purpose Granular Fertilizer (link to Amazon) for your boxwood plant’s pH issues. Work the fertilizer into the soil, then water it to release numerous nutrients.
This fertilizer is packed with calcium, which is known for increasing the soil’s pH. One four-pound bag is enough for several applications throughout the yard.
Do Boxwoods Like Acidic or Alkaline Soils? (PAA)
Boxwoods prefer neutral soils that aren’t too acidic or alkaline. The soil’s pH should be as close to 7 as possible. Boxwoods can handle a pH range between 6.5 to 7.5, though. If the soil gets too acidic or alkaline, it can cause long-term damage to the plant.
Boxwoods thrive in a 6.5 pH, but they can tolerate soils with a pH of up to 7.5 (source). They’re much more sensitive to fluctuation or extreme pHs than most other evergreen plants. While they can withstand everchanging nutrient densities, they’re quite reliant on having a steady pH.
Here’s a quick rundown of how you can change the soil if it’s too acidic or alkaline:
- Use limestone to raise the pH. Limestone is available in sheets or granules. A thin layer of lime instantly increases the soil’s alkalinity, making it much safer for boxwood plants to grow.
- Add sulfur-based pH adjusters to the soil if you want to lower the pH. If the pH is too high, it’ll be very difficult for the plant to grow with enough water and nutrients. It can also encourage fungal growth. (See our guide to managing alkaline soil).
- Aerate the soil and use a neutral water source. You can test your city’s water pH to know if it’s neutral (many city-based water sources are neutral or alkaline). This is a slow process, but it’s good for minor pH adjustments.
Unfortunately, acidic soil can reverse all of the good efforts you’ve gone through for your boxwoods. Read on to know the common signs of a boxwood sitting in soil with a low pH.
What Happens if a Boxwood’s Soil Is Too Acidic?
If a boxwood’s soil is too acidic, the roots will burn, the leaves will weaken, and the plant won’t be able to absorb enough water. Additionally, the acidic soil can make the stems and leaves wilt, causing the plant to break at the base. Always monitor soil adjustments to ensure they don’t go too far in either direction.
Let’s analyze each of these issues in detail below.
- Too much soil acidity can prevent the roots from absorbing enough nutrients. The roots are singed at the tips, which means there’s not enough surface area to pull minerals, carbon, nitrogen, and other nutrients from the dirt. They’ll also appear much thinner than usual.
- The roots and leaves will look damaged and weak. Not only can this damage the plant’s structural support system, but it also makes them much more susceptible to various plant diseases. Acidic soil combined with excessive moisture flooding can lead to root rot, which is one of the worst things that can happen to a boxwood.
- Your boxwood won’t be able to absorb moisture and send it through the leaves. This will cause the leaves to wilt, but it also means the plant won’t be able to grow until you fix the issue. Acidic soil is especially dangerous to brand-new plants and older plants. However, it can typically be fixed without causing permanent problems.
- Structural damage is a common symptom of acidic soil around boxwood plants. When the plant’s roots are weak, it becomes top-heavy. This means the base of each stem can crack and fall on the lower layers. You’ll also notice the stems look hollow and feel crunchy because they don’t have enough water in them.
- The leaves will look yellow or brown if the soil’s pH is too low. This is a combination of the aforementioned lack of nutrient absorption and not having enough water to produce chlorophyll. Boxwoods need water and sunlight to stay green, but they won’t look vibrant or green if the roots are damaged from acidity.
You can reverse the soil’s acidity by adding lime on top of the dirt. Keep in mind that too much limestone can send the soil’s pH far too high.
Follow the manufacturer’s instructions to know exactly how much limestone your boxwood’s soil needs based on the square footage and soil composition.
While boxwoods don’t love acidic soil, they can grow in a variety of soil compositions. However, it’s important to maintain the pH to keep the plant looking green and feeling healthy.
Many experts recommend sulfur and lime for adjusting the soil’s pH. I want to add though that you can often balance the pH of the soil simply by incorporating organic matter into from a quality finished compost.