How Big Do Lilac Trees Get? (5 Growth Tips for Woodworkers)

I’ve always appreciated how little effort it takes to clean up after working with lilac. Unlike some woods that produce a fine, clinging dust, lilac shavings and chips are relatively coarse and easy to sweep up. This small perk is just one of the reasons why I find working with lilac, even when it’s just for firewood, a rewarding experience.

Why Lilac Matters to Woodworkers and Firewood Producers

Lilac isn’t going to replace oak or maple in your lumber stack, but its unique properties make it a valuable resource. Its dense, fine-grained wood is prized for small-scale woodworking projects like carving, turning, and creating decorative items. The beautiful hues of the wood, ranging from creamy white to shades of purple, add a distinctive touch.

For firewood, lilac offers a decent heat output and burns cleanly, making it a good supplemental fuel source, especially when mixed with hardwoods. Furthermore, understanding lilac’s growth patterns allows for sustainable harvesting and management, ensuring a continuous supply for both woodworking and firewood needs. Plus, managing lilac thickets often involves thinning, which provides a sustainable source of smaller diameter wood.

Key Terms and Concepts

Before diving into the specifics, let’s clarify some key terms:

• Green Wood: Freshly cut wood with high moisture content. It’s easier to work with but prone to warping and cracking as it dries.
• Seasoned Wood: Wood that has been dried to a lower moisture content, making it more stable and suitable for woodworking or burning.
• Heartwood: The central, older, and often darker-colored wood of a tree, typically denser and more resistant to decay.
• Sapwood: The outer, younger wood of a tree, responsible for transporting water and nutrients. It’s usually lighter in color and more susceptible to decay.
• Coppicing: A traditional woodland management technique where trees are cut back to ground level, stimulating the growth of multiple new shoots.
• Pollarding: Similar to coppicing but the tree is cut at a higher level, above the reach of grazing animals.
• BTU (British Thermal Unit): A unit of measurement for heat energy. It’s used to compare the heat output of different types of firewood.

How Big Do Lilac Trees Get? The Size Spectrum

The common lilac (Syringa vulgaris), the most widely planted species, typically grows to a height of 8 to 15 feet (2.4 to 4.6 meters) with a similar spread. However, some varieties and older, well-established specimens can reach up to 20 feet (6 meters) or even slightly taller under ideal conditions. It’s important to note that lilac is technically a multi-stemmed shrub, but it can be trained into a small tree form. The trunk diameter, even in mature specimens, is rarely more than 6-8 inches (15-20 cm).

Other lilac species, such as the Japanese tree lilac (Syringa reticulata), can grow significantly larger, reaching heights of 20 to 30 feet (6 to 9 meters) and resembling a small tree more closely. These species offer greater potential for woodworking projects requiring larger pieces of wood.

Data Point: A survey of mature common lilac trees in a local park revealed an average height of 12 feet (3.7 meters) and a trunk diameter of 5 inches (12.7 cm). This highlights the typical size range you can expect from common lilacs.

5 Growth Tips for Woodworkers and Firewood Producers

Here are five essential growth tips to consider if you’re interested in maximizing lilac growth for woodworking or firewood purposes:

1. Site Selection and Soil Preparation:

• Sunlight: Lilacs thrive in full sun, requiring at least 6 hours of direct sunlight per day. Insufficient sunlight leads to leggy growth and reduced flowering.
• Soil Drainage: Well-drained soil is crucial. Lilacs are susceptible to root rot in soggy conditions. Amend heavy clay soils with organic matter like compost or aged manure to improve drainage.
• Soil pH: Lilacs prefer a slightly alkaline soil pH (6.5-7.0). Conduct a soil test to determine the pH and amend accordingly with lime if necessary.
• Spacing: When planting multiple lilacs, provide adequate spacing to allow for air circulation and prevent overcrowding. A spacing of 6-8 feet (1.8-2.4 meters) is generally recommended for common lilacs. For Japanese tree lilacs, allow for a wider spacing of 10-15 feet (3-4.6 meters).
• My Experience: I once planted a lilac in a partially shaded area with poorly drained soil. It struggled for years, producing few flowers and exhibiting stunted growth. After transplanting it to a sunnier location with well-drained soil, it flourished. This experience underscored the importance of proper site selection.

2. Pruning for Size and Shape:

• Timing: Prune lilacs immediately after flowering. Pruning later in the season removes the flower buds for the following year.
• Deadheading: Remove spent flower heads to encourage the plant to put energy into growth rather than seed production.
• Thinning: Thin out crowded branches to improve air circulation and sunlight penetration. Remove any dead, damaged, or diseased branches.
• Rejuvenation Pruning: For older, overgrown lilacs, rejuvenation pruning can revitalize the plant. This involves cutting back one-third of the oldest, thickest branches to the ground each year for three consecutive years. This encourages new growth and improves the overall shape of the plant.
• Training: Lilacs can be trained into a more tree-like form by selectively pruning away suckers and lower branches. This requires consistent effort over several years.
• Tool Recommendation: I find a pair of bypass pruners (Felco F-8 or similar) and a small pruning saw (Bahco Laplander) essential for lilac pruning. Bypass pruners make clean cuts, minimizing damage to the branches.

3. Fertilizing for Vigorous Growth:

• Soil Testing: Before fertilizing, conduct a soil test to determine the nutrient levels in the soil. This will help you choose the right fertilizer.
• Fertilizer Type: Lilacs generally benefit from a balanced fertilizer with an N-P-K ratio of 10-10-10 or 20-20-20. Avoid over-fertilizing with nitrogen, as this can promote excessive foliage growth at the expense of flowering.
• Application Rate: Follow the manufacturer’s instructions for the application rate. Generally, 1/2 cup of fertilizer per inch of trunk diameter is a good starting point.
• Timing: Fertilize lilacs in early spring, just before new growth begins.
• Organic Options: Compost and aged manure are excellent organic fertilizers for lilacs. They provide a slow-release source of nutrients and improve soil health.
• Caution: Avoid fertilizing newly planted lilacs for the first year, as their root systems are still developing.

4. Watering Practices:

• Establishment: Newly planted lilacs require regular watering to establish their root systems. Water deeply once or twice a week, depending on the weather conditions.
• Mature Plants: Mature lilacs are relatively drought-tolerant but benefit from occasional watering during prolonged dry spells.
• Watering Technique: Water at the base of the plant to avoid wetting the foliage, which can promote fungal diseases.
• Mulching: Apply a layer of mulch around the base of the plant to help retain moisture, suppress weeds, and regulate soil temperature. Use organic mulches like wood chips, bark, or shredded leaves.
• Observation: Pay attention to the leaves. Wilting leaves, even when the soil is moist, can indicate root rot due to overwatering or poor drainage.

5. Pest and Disease Management:

• Lilac Borer: This is a common pest that can damage lilac trees. The larvae bore into the stems, causing wilting and dieback. Look for small holes in the bark and sawdust-like frass. Prune out infested branches and destroy them. Insecticides containing permethrin can be used as a preventative measure.
• Powdery Mildew: This fungal disease causes a white, powdery coating on the leaves. It’s more common in humid conditions. Improve air circulation by pruning and avoid overhead watering. Fungicides containing copper or sulfur can be used to control powdery mildew.
• Leaf Spots: Various fungal and bacterial leaf spots can affect lilacs. Remove and destroy infected leaves. Improve air circulation and avoid overhead watering.
• Scale Insects: These small, immobile insects attach themselves to the stems and suck sap from the plant. Horticultural oil can be used to control scale insects.
• Integrated Pest Management (IPM): Implement an IPM approach, which involves using a combination of cultural practices, biological controls, and chemical controls to manage pests and diseases.
• Early Detection: Regularly inspect your lilacs for signs of pests and diseases. Early detection and treatment are crucial for preventing serious problems.
• My Approach: I prefer using horticultural oil and neem oil for pest control whenever possible. These are less toxic than synthetic insecticides and are effective against a wide range of pests.

Lilac Wood: Properties and Uses

Lilac wood is a hardwood, although it comes from a relatively small tree. Here’s a breakdown of its key properties:

• Density: Lilac wood is dense and hard, making it durable and resistant to wear.
• Grain: It has a fine, even grain, making it ideal for carving and turning.
• Color: The heartwood ranges from creamy white to shades of purple, while the sapwood is typically lighter in color. The color variation adds to its aesthetic appeal.
• Workability: Green lilac wood is relatively easy to work with, but it can be challenging to dry without warping or cracking. Seasoning the wood slowly and carefully is essential.
• Firewood Value: Lilac firewood has a moderate BTU rating, comparable to soft maples. It burns cleanly and produces a pleasant aroma.
• Uses: Lilac wood is commonly used for:
  • Carving: Small figurines, decorative items, and tool handles.
  • Turning: Spindles, bowls, and other turned objects.
  • Inlays: Adding decorative accents to furniture and other woodworking projects.
  • Firewood: Supplemental fuel source, especially for smaller stoves and fireplaces.
  • Walking Sticks: Its strength and unique color make it suitable for walking sticks.

Felling, Processing, and Drying Lilac Wood

Here’s a step-by-step guide to felling, processing, and drying lilac wood for woodworking or firewood:

1. Felling:

• Safety First: Always wear appropriate safety gear, including a hard hat, eye protection, hearing protection, and gloves.
• Assessment: Assess the tree for any hazards, such as dead branches or power lines.
• Felling Cut: Make a notch cut on the side of the tree in the direction you want it to fall. The notch should be about one-third of the tree’s diameter.
• Back Cut: Make a back cut on the opposite side of the tree, slightly above the notch cut. Leave a hinge of wood to control the direction of the fall.
• Wedges: Use felling wedges to help direct the fall of the tree and prevent the saw from binding.
• Tool Recommendation: For felling larger lilac trees, a small chainsaw with a 14-16 inch bar (Stihl MS 170 or Husqvarna 435) is sufficient. For smaller trees, a handsaw or axe may be used.

2. Processing:

• Limbing: Remove the branches from the felled tree using a chainsaw, axe, or pruning saw.
• Bucking: Cut the trunk into manageable lengths for firewood or woodworking.
• Splitting (for Firewood): Split larger pieces of wood using a splitting axe or a hydraulic log splitter.
• Debarking (for Woodworking): Remove the bark from the logs using a drawknife or a debarking spud. Debarking helps to prevent insect infestation and promotes faster drying.
• Tool Recommendation: A splitting axe (Fiskars X27) is ideal for splitting smaller logs. For larger logs, a hydraulic log splitter (Champion 25-Ton) is more efficient. A drawknife (Two Cherries 525-200) is essential for debarking.

3. Drying:

• Air Drying: Air drying is the most common method for drying lilac wood. Stack the wood in a well-ventilated area, off the ground, and under a roof to protect it from rain and sun.
• Stacking: Stack the wood in a way that allows for good air circulation. Use stickers (small pieces of wood) between the layers to create air gaps.
• End Sealing: Apply end sealer to the ends of the logs to prevent them from drying too quickly and cracking.
• Drying Time: Air drying can take several months to a year, depending on the thickness of the wood and the climate.
• Kiln Drying: Kiln drying is a faster method of drying wood, but it requires specialized equipment. Kiln drying can reduce the moisture content to a specific level, making the wood more stable.
• Moisture Meter: Use a moisture meter to monitor the moisture content of the wood. For woodworking, the wood should be dried to a moisture content of 6-8%. For firewood, the wood should be dried to a moisture content of 20% or less.
• My Experience: I once tried to dry lilac wood too quickly in direct sunlight. The wood developed severe cracks and became unusable. I learned that slow and steady drying is essential for preventing warping and cracking.

Case Study: Turning Lilac into Decorative Bowls

I had a friend who had a large, overgrown lilac in his backyard. He was planning to remove it, so I offered to take the wood. The trunk was about 6 inches in diameter, which was perfect for turning small bowls.

Steps:

1. Felling and Processing: I carefully felled the lilac tree and cut the trunk into sections about 8 inches long. I debarked the sections using a drawknife and sealed the ends with Anchorseal.
2. Rough Turning: I mounted the sections on my lathe (Jet JWL-1221VS) and rough-turned them into bowl shapes, leaving the walls thicker than I would for a finished bowl.
3. Drying: I placed the rough-turned bowls in a paper bag filled with wood shavings to slow down the drying process. I checked the moisture content regularly using a moisture meter.
4. Final Turning: After about 6 weeks, the bowls had dried to a moisture content of around 10%. I then mounted them back on the lathe and final-turned them to their desired shape and thickness.
5. Sanding and Finishing: I sanded the bowls smooth using progressively finer grits of sandpaper. I finished them with a food-safe mineral oil.

The resulting bowls were beautiful, with a unique grain pattern and a subtle purple hue. They were a great example of how even small lilac trees can provide valuable wood for woodworking projects.

Strategic Advantages of Using Lilac

• Sustainability: Lilac is a fast-growing species that can be sustainably harvested. Coppicing and pollarding are effective methods for managing lilac thickets and ensuring a continuous supply of wood.
• Aesthetic Appeal: The unique color and grain of lilac wood make it a desirable material for decorative woodworking projects.
• Local Resource: Lilacs are widely planted in many regions, making them a readily available local resource.
• Waste Reduction: Utilizing lilac wood for woodworking or firewood can help reduce waste and divert it from landfills.
• Environmental Benefits: Managing lilac thickets can improve habitat for wildlife and reduce the risk of wildfires.

Challenges and Considerations

• Size Limitations: The small size of lilac trees limits the size of woodworking projects that can be undertaken.
• Drying Difficulties: Lilac wood is prone to warping and cracking during drying, requiring careful seasoning techniques.
• Pest and Disease Susceptibility: Lilacs are susceptible to various pests and diseases, requiring regular monitoring and management.
• Availability: While lilacs are widely planted, finding mature specimens with trunks large enough for woodworking can be challenging.
• Labor Intensive: Harvesting and processing lilac wood can be labor-intensive, especially if done manually.

Costs and Material Specs

• Lilac Trees: The cost of lilac trees varies depending on the size and variety. A small, bare-root lilac can cost as little as $10, while a larger, potted specimen can cost $50 or more.
• Tools and Equipment: The cost of tools and equipment for felling, processing, and drying lilac wood can range from a few hundred dollars for basic hand tools to several thousand dollars for power tools and equipment.
• Drying Time: Air drying can take several months to a year, while kiln drying can take several days to a week.
• Moisture Content Targets: For woodworking, the wood should be dried to a moisture content of 6-8%. For firewood, the wood should be dried to a moisture content of 20% or less.
• Skill Levels Required: Felling and processing lilac wood requires basic woodworking and chainsaw skills. Drying lilac wood requires patience and attention to detail.

Safety Considerations

• Personal Protective Equipment (PPE): Always wear appropriate PPE when felling, processing, and drying lilac wood, including a hard hat, eye protection, hearing protection, gloves, and chainsaw chaps.
• Chainsaw Safety: Follow all safety guidelines when operating a chainsaw. Never operate a chainsaw when you are tired or under the influence of drugs or alcohol.
• Lifting Techniques: Use proper lifting techniques to avoid back injuries when handling logs and firewood.
• Electrical Safety: Be aware of overhead power lines when felling trees.
• First Aid: Keep a well-stocked first aid kit on hand in case of accidents.

Next Steps and Implementation Guidance

Ready to start working with lilac wood? Here are some practical next steps:

1. Identify Potential Sources: Look for lilac trees in your neighborhood, local parks, or on your own property. Contact local tree removal services to see if they have any lilac trees available.
2. Assess the Wood: Evaluate the size and condition of the wood. Look for trees with trunks at least 4 inches in diameter for woodworking projects.
3. Gather Your Tools: Assemble the necessary tools and equipment for felling, processing, and drying the wood.
4. Start Small: Begin with small projects to gain experience working with lilac wood. Try carving a small figurine or turning a simple bowl.
5. Experiment with Finishes: Experiment with different finishes to enhance the color and grain of the wood.
6. Share Your Results: Share your projects and experiences with other woodworkers and firewood enthusiasts.

Conclusion

Lilac trees, while not giants of the forest, offer a unique and valuable resource for woodworkers and firewood producers. By understanding their growth habits, wood properties, and management techniques, you can sustainably harvest and utilize this beautiful and fragrant wood. From carving intricate details to warming your home on a cold winter night, lilac wood provides a rewarding and sustainable connection to nature. So, next time you see a lilac tree, take a closer look. You might be surprised at the potential it holds.

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