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When it comes to showy perennials its hard to beat a hydrangea. Those flowering shrubs covered with giant bubbles of pink, white, purple, or blue blooms are a staple of practically every well-designed garden landscape in your neighborhood. Its certainly true for ours!
If youre having difficulty keeping your hydrangeas blooming—or are considering planting a few this year, and want to ensure theyre as successful as possible—this guide will help you to understand what hydrangeas need, how to (and where) to plant them, and which hydrangea is right for your yard.
There are a few different types of hydrangeas, including Big Leaf, Panicle, Cascade, Climbing, and Smooth. While they all have similar needs, there is enough variety to ensure that you should be able to find a variety thats right for your situation. (Check out our guide to the best hydrangeas for every climate.)
Hydrangeas are a beloved garden shrub, prized for their large colorful flower heads that bloom throughout the summer. But much of the magic happens underground, through the hydrangea’s intricate root system. So exactly how deep do hydrangea roots grow?
Understanding the depth and spread of hydrangea roots gives key insights into properly caring for these ornamental shrubs. It helps ensure proper watering, spacing, fertilizing and winter protection. Matching your care practices to their root habits allows hydrangeas to thrive season after season.
An Overview of Hydrangea Root Types
Hydrangeas develop two main types of roots
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Surface roots – These grow horizontally just below the top of the soil. They absorb moisture and nutrients.
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Deep roots – These grow downwards, anchoring the plant and storing water reserves.
Most of the root system is concentrated in the upper 12-24 inches of soil. But some deep anchor roots can reach down 2-3 feet or more depending on the variety.
Typical Root Depth Range
In most cases, here is how deep hydrangea roots typically grow:
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Surface roots – These grow horizontally 6-12 inches deep in the soil.
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Deep roots – These can grow downwards anywhere from 1-3 feet deep or more.
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Majority of roots – Most of the root mass is concentrated in the top 12 inches of soil.
So while hydrangeas develop some deep anchor roots, their main root network is fairly shallow. Exact depth ranges can vary based on the type of hydrangea, age of plant, soil conditions and other environmental factors.
What Impacts Hydrangea Root Depth?
Several key factors influence how deep hydrangea roots are able to grow:
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Soil type – Loose, nutrient-rich soils allow for deepest root growth. Heavy clay soils can restrict depth.
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Age of plant – Younger hydrangeas have shallower roots that deepen as the plant matures.
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Water availability – Drier conditions promote deeper root growth as the plant searches for moisture.
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Variety – Oakleaf hydrangea, for example, is known to have the deepest roots vs. other types.
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Climate – Extreme cold or temperature fluctuations may force roots to grow deeper for protection.
Understanding what impacts root depth helps you better understand how deep your hydrangeas’ roots are likely to grow. It also allows you to adjust care accordingly.
The Role of Surface vs. Deep Roots
Surface and deep hydrangea roots serve different but complementary purposes:
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Surface roots – Absorb moisture and nutrients. Spread horizontally to access resources. Most active in nutrient uptake.
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Deep roots – Provide structural stability and anchoring. Store water reserves for dry periods. Tap into deeper soil nutrients when needed.
This combination of shallow and deep roots suits the hydrangea’s needs as a flowering garden shrub. It allows them to thrive in various climates and soil types.
Caring for Hydrangeas Based on Root Depth
Now that we understand how deep hydrangea roots typically grow, how does that inform care? Here are some key tips:
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Water – Water thoroughly to moisten deep roots, not just surface roots.
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Mulch – Use mulch to maintain moisture levels in soil for shallow surface roots.
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Fertilize – Replenish nutrients that deep roots access over time.
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Prune – Prune judiciously to promote vigorous root growth.
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Avoid soil compaction – Allow roots to spread freely without compacted soil restricting growth.
Adjusting your practices based on rooting depths and habits helps keep hydrangeas healthy and flowering profusely.
Root Pruning for Rejuvenation
Selectively pruning hydrangea roots serves an important purpose – it rejuvenates plants and stimulates new growth. Here are some tips:
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When to prune – Late winter when the plant is dormant. Avoid actively growing times.
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How to prune – Uncover roots and trim out crossed, congested sections.
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Post-pruning care – Water consistently and fertilize to aid recovery.
Done properly every few years, root pruning helps keep hydrangeas vigorous and flowering. It prevents root congestion and declining health.
Troubleshooting Common Root Problems
Watch for these issues that can affect hydrangea roots:
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Root rot – Caused by overly wet soil. Improve drainage.
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Root competition – Nearby trees stealing water and nutrients. Space properly.
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Pests – Nematodes or other pests attacking roots. Apply appropriate treatment.
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Cold damage – Harsh winters can damage shallow roots. Use mulch for insulation.
Catching root problems early allows you to take corrective care to get your hydrangeas thriving again.
Digging Into Hydrangea Root Depths
To properly care for hydrangeas, it’s helpful to understand how deep their roots grow. While depth ranges can vary, most hydrangea roots concentrate in the top 12 inches of soil. With some growing several feet deep for anchoring and water reserves.
Use this knowledge of their rooting depths and habits to tailor water, spacing, fertilizer and all care practices. Doing so ensures lush, flowering hydrangea shrubs that will thrive in your landscape for years to come.
How Often to Water Hydrangeas
Newly planted hydrangeas need plenty of water to get established. Be sure to water frequently for the first year or two. Established plants like moist soil during the growing season. If it hasn’t rained in a while water your plants deeply one to two times per week. Watering deeply will ensure that the water moistens the entire root system.
How to Plant Hydrangeas
While they can grow in any type of soil hydrangeas grow best in soil that is hummus-rich. If your soil has a high clay content it can help to amend it with compost and organic matter before planting. (Here are some tips for composting at home.)
It’s also important to look at the grow tag to see how big the mature plant will be and the spacing recommendations.
Once you have chosen your location and amended the soil you are ready to plant!
- Start by digging a hole that is twice the width, and the same depth as the container.
- Set the plant in the hole so that the top of the root ball is the same height or ever-so-slightly higher than the soil surface.
- Back fill in the hole halfway with the soil and water generously.
- Once the water is absorbed, fill the hole with soil and water again.
- Because hydrangeas have shallow root systems, mulch well after planting to prevent them from drying out.
How to Propagate Hydrangeas |Simple Way to Get Cuttings to Root Faster|
FAQ
Do hydrangeas have deep or shallow roots?
Hydrangea roots are generally shallow, with a depth typically ranging from 12 to 24 inches (30 to 60 cm). While they don’t delve deep into the soil, their roots tend to spread out laterally, extending beyond the plant’s canopy, often 2 to 3 feet (60 to 90 cm).
Are hydrangeas hard to dig out?
Digging up hydrangeas can be challenging, especially for larger, established shrubs, due to their extensive root systems. While the roots are fibrous and not as deep as some trees, they can be wide and dense, requiring a significant amount of digging.
How deep should soil be for hydrangeas?
Plant hydrangeas in spring after the last frost or in fall before the first frost of the season. Dig a hole that is twice the diameter and as deep as the pot of your hydrangea. Test to ensure that the root ball will be level or just above the soil surface by placing the pot into the hole to check.
What is the 1/3 rule for hydrangeas?
How deep are Hydrangea roots?
The depth of hydrangea roots can vary depending on several factors, including the hydrangea variety, soil type, and environmental conditions. In general, here’s what you can expect: Shallow Roots: Surface roots typically extend outward from the plant’s base for about 3 to 4 feet. These roots can be found within the top 6 to 12 inches of soil.
What kind of soil do hydrangeas need?
The ideal soil composition for hydrangeas is a well-draining, moist, and moderately fertile acidic soil. The shallow fibrous root system makes hydrangeas sensitive to drought and frost, and it’s crucial to care for the roots to ensure a healthy and blooming plant. How Deep Do Hydrangea Roots Actually Go?
How much space does a hydrangea need?
Hydrangea roots go about 6 inches under the soil and need about 3-5 feet of space to get all the nutrients and moisture to grow to their full potential. Some hydrangeas also have stems or roots above the ground and grow about 15 feet. Hydrangeas mostly have a non-invasive shallow root system. Hydrangea is commonly known as hydrangea or hortensia.
Why do hydrangeas grow deep?
Heavy clay restricts depth. Age of plant – Young hydrangeas have shallower roots that deepen with age. Water availability – Drier conditions promote deep root growth to find moisture. Hydrangea variety – Oakleaf hydrangea roots grow deepest. Others are variable.
Do hydrangeas have deep roots?
Looking at the vigorous growth of a Hydrangea’s stems, it’s easy to assume they must be matched by a deep and stubborn root system underground. But Hydrangea roots are actually surprisingly shallow. They don’t form a central taproot like rhododendrons and shrubs.
How do you plant a hydrangea?
Gently remove the hydrangea from its container and inspect the root ball, snipping off any dead or rotting parts and teasing free the roots if the plant is especially root-bound. Dig a hole as deep as the root ball and 2 to 3 times as wide. The base of the plant (where the stem meets the soil) should be level with the top of the planting hole.