Sun Joe HJ604C Cordless Grass Shears Trimmer Review: The Pint-Sized Powerhouse with a Hidden Flaw

There’s a certain kind of frustration that only a gardener knows. It’s the feeling you get after spending an hour mowing the lawn to perfection, only to look at the edges and see a mess. The grass creeping over the patio stones, the unruly tufts around the mailbox, the delicate dance required to trim around your prized rose bushes without decapitating them. For years, my solution was a powerful, noisy string trimmer. It was effective, but “precise” was not in its vocabulary. More often than not, I’d end up scalping the lawn, sending dirt and debris flying, and nicking the very plants I was trying to protect. It felt like using a sledgehammer to crack a nut. This led me on a quest for a tool that offered finesse over brute force, a surgical instrument for the final, perfecting touches on a well-manicured lawn. That’s the exact niche the Sun Joe HJ604C Cordless Grass Shears Trimmer aims to fill.

What to Consider Before Buying a Cordless Shear and Trimmer

A cordless grass shear or hedge trimmer is more than just an item; it’s a key solution for achieving that polished, professional look in your garden without the hassle of cords or the imprecision of larger tools. It solves the problem of “the last 10%,” tidying up areas where mowers and string trimmers can’t safely or effectively reach. The main benefits are unparalleled control, lightweight handling, and the freedom to move anywhere in your yard. It’s about turning a tedious chore into a quick, satisfying task, giving you clean lines along walkways, immaculate borders around flower beds, and neatly shaped decorative shrubs.

The ideal customer for this type of product is someone with small to medium-sized gardens who values meticulous detail. This includes homeowners with intricate landscaping, patio homes with container gardens, or anyone who finds larger yard tools too heavy or cumbersome. We’ve found these tools to be a blessing for older gardeners or those with physical limitations like arthritis or carpal tunnel, as the low weight and powered cutting action dramatically reduce strain. However, it might not be suitable for those who need to clear large, overgrown areas or cut through thick, woody branches. If your main task is taming a 50-foot privacy hedge of mature privet, you should be looking at a full-sized, heavy-duty hedge trimmer instead.

Before investing, consider these crucial points in detail:

• Dimensions & Weight: The primary advantage of a tool like this is its maneuverability. Look for a unit that is lightweight, typically under 3 pounds, and has an ergonomic handle that fits comfortably in your hand. The dimensions will affect how easily you can get into tight spaces, so a compact design is a major plus for detailed work.
• Power & Performance: Voltage is a key indicator of power. A 7.2V system, like the one in the Sun Joe HJ604C, is generally sufficient for grass and soft new growth on shrubs. Pay attention to the blade speed (RPM) and the maximum cutting diameter, which is usually around 1/4 to 3/8 of an inch. Anything thicker will require manual pruners or a more powerful tool.
• Materials & Durability: The housing will almost always be plastic to keep the weight down, but the quality of that plastic matters. The most critical components are the blades and the internal gears. Hardened steel blades will stay sharp longer. As we’ll discuss in detail, the internal drive gear can be a weak point, with some models using plastic gears that may strip under pressure, so build quality is paramount.
• Battery Life & Ease of Use: Look for a lithium-ion battery, which offers a better power-to-weight ratio and doesn’t suffer from the “memory effect” of older battery types. Check the estimated run time and charge time. Features like a tool-free blade change, a safety switch to prevent accidental start-up, and clear charging indicators significantly improve the user experience.

While the Sun Joe HJ604C Cordless Grass Shears Trimmer is an excellent choice for its niche, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:

First Impressions: Unboxing the Sun Joe HJ604C

Upon opening the box, the first thing that struck me about the Sun Joe HJ604C Cordless Grass Shears Trimmer was its compact size and remarkably low weight. At just over two and a half pounds, it felt more like a kitchen appliance than a piece of yard equipment. The main unit, two blade attachments (a 4-inch grass shear and a 6-inch shrubber blade), blade covers, and a small wall charger were all neatly packed. There’s no real assembly required; you simply choose a blade, click it into place, and you’re ready to charge. The body is made of a sturdy black plastic that feels solid enough for its intended use, and the ergonomic handle provided a comfortable, secure grip. The safety switch, which must be depressed before the trigger will engage, is intuitively placed for thumb operation. Swapping the blades was a simple, tool-free process: just press a button, slide the bottom plate off, and exchange the blades. It’s a far cry from the complex, gas-guzzling beasts of the past, designed for accessibility and immediate use.

A Deep Dive into the Sun Joe HJ604C’s Real-World Performance

A tool can look great on the spec sheet, but the real test is out in the garden. We put the Sun Joe HJ604C through its paces over several weeks, tackling everything from unruly lawn edges along a concrete path to shaping boxwoods and trimming back ornamental grasses. Our extended testing revealed a tool that is both incredibly useful and has one significant, character-defining flaw.

Ergonomics and Ease of Use: A Gardener’s Best Friend

The single greatest strength of the Sun Joe HJ604C Cordless Grass Shears Trimmer is its incredible ease of use. Weighing in at only 2.5 pounds, it feels almost effortless to wield. During our tests, we could use it for 30-40 minutes continuously without any of the arm fatigue or vibration numbness associated with larger trimmers. This observation is strongly supported by a chorus of users who praise its accessibility. One user, who suffers from carpal tunnel in both hands, described it as a “huge difference,” allowing them to garden for hours without the pain that manual clippers induced. Another, a 74-year-old gardener with weak arms, noted they could manage trimming a large hedge by using both hands and taking short breaks. This is where the Sun Joe truly shines. It empowers people to continue a hobby they love by removing the physical barriers that heavier equipment can create.

The controls are simple and safe. The dual-action safety switch and trigger are easy to operate with one hand, preventing any accidental starts when you’re carrying it or changing blades. The tool-free blade swap mechanism worked flawlessly every time, converting from a grass shear to a hedge trimmer in under 30 seconds. This seamless transition encourages you to use the right tool for the job, rather than trying to make one blade do everything. For detail work, edging, and light shaping, the ergonomics are nearly perfect.

Dual-Blade Versatility: The Right Tool for a Precise Job

The 2-in-1 functionality isn’t just a gimmick; it genuinely adds value. We started with the 4-inch grass shear blade, tackling the overgrown edges along our driveway. It cut through standard lawn grass like butter, creating a crisp, clean line that was impossible to achieve with our string trimmer. It excelled at getting into tight corners and trimming around the base of fence posts. As one user aptly put it, a weedwacker is “just too chaotic” for clean lines, and this tool provides the necessary control. We found it perfect for snipping the grass that grows through cracks in the pavement and for creating neat circles around trees and shrubs.

Switching to the 6-inch hedge trimmer blade, we tested it on some small boxwood shrubs and a rosemary bush. Here, its limitations become clearer. The tool is specified for branches up to 0.3 inches, and we found this to be accurate. It sails through soft, new growth, making it ideal for light shaping and maintaining small decorative bushes. However, the moment it encountered a slightly tougher or thicker branch, the blades would jam. We confirmed what other users have reported: it struggles with anything over a quarter-inch and is not meant for serious trimming or reduction. It’s a finishing tool, perfect for a quick touch-up after the heavy work is done or for maintaining plants that only require a light shearing. One reviewer successfully trimmed two large bushes over 40 minutes, noting that while it was slower than a high-powered trimmer, it did a “nicer job” with more precision. This perfectly encapsulates its role: it trades speed and raw power for control and finesse.

Battery Life and Charging Insights

The 7.2V lithium-ion battery provides a respectable amount of runtime for a tool of this size. In our tests, we consistently got between 40 and 50 minutes of continuous use on a full charge, which was more than enough time to complete most detailed trimming tasks around the yard. The power delivery remained consistent until the very end of the charge, with no noticeable slowdown. Recharging the unit from empty took about 4.5 to 5 hours.

There appears to be some variance in the charging system depending on the model’s manufacturing date. Some older user reports mention a charger without an automatic shut-off or a full-charge indicator, cautioning against leaving it plugged in indefinitely. However, our test model, and those mentioned in more recent reviews, clearly featured an indicator light that glowed red while charging and turned green when the battery was full. This is a significant quality-of-life improvement. For peace of mind, we still recommend unplugging the charger once the battery is full, but the indicator light on newer models removes the guesswork and risk of overcharging, which is a welcome update and one worth looking for if you decide to purchase this handy tool.

The Achilles’ Heel: A Question of Durability

For all its strengths, the Sun Joe HJ604C Cordless Grass Shears Trimmer has a well-documented weak point: its internal drive gear. Inside the housing, a small metal gear on the motor drives a larger plastic (nylon) gear that actuates the blades. This design is likely a cost- and weight-saving measure, but it creates a potential failure point. If the blades are jammed on a branch that is too thick, the motor continues to spin, and the metal gear can easily strip the teeth off the softer plastic gear. Several users have reported this exact issue, some even providing photos of the stripped gear after the tool abruptly stopped working. Once this happens, the tool is rendered useless.

Compounding this problem is the lack of available spare parts. Users who have contacted the manufacturer to purchase a replacement gear have been told the part is not sold separately. Similarly, replacement blades can be difficult to find, with some long-term owners noting they are perpetually on backorder. This effectively turns what could be a simple, inexpensive repair into a situation where the entire unit must be replaced. While many users report years of flawless service—one reviewer owns three units, the oldest of which has worked hard since 2018—it’s crucial for a potential buyer to understand this limitation. The key to longevity with the Sun Joe HJ604C is to respect its limits. Use it only for grass and soft, new growth, and never try to force it through thick or woody material. If the blades jam, stop immediately rather than trying to power through.

What Other Users Are Saying

After analyzing dozens of user experiences, a clear picture of the Sun Joe HJ604C emerges. The overwhelming majority of positive feedback centers on its light weight and ease of use. A user who bought it for just $22 on sale said, “now I can safely say it’s worth every penny,” praising its ability to cut grass “like butter” for clean landscaping lines. Another long-term owner, who purchased their first unit in 2018 and a second in 2019, confirms their durability for light tasks, noting both “still work fine” after years of use.

On the other side of the coin, the negative feedback is almost laser-focused on the internal plastic gear. One frustrated user stated, “Both suffered same problem. Hit a snag and the cheap plastic gear… is worn out by the metallic gear of the motor.” Another provided a detailed account, complete with a photo, showing the stripped teeth after less than two months of light use. This durability concern is the single most significant issue raised by customers. Some also mentioned issues with customer service, particularly regarding the unavailability of replacement parts like blades or gears, which is a valid frustration for an otherwise beloved tool.

How Does the Sun Joe HJ604C Compare to the Alternatives?

The Sun Joe HJ604C operates in a competitive space, but its specific combination of features and low price gives it a unique position. It’s important to see how it stacks up against other options to know if it’s truly the right choice for your needs.

1. DEWALT DCHT820B 22-Inch Cordless Hedge Trimmer

Comparing the Sun Joe to the DEWALT DCHT820B is like comparing a scalpel to a machete. The DEWALT is a powerful, full-sized hedge trimmer designed for serious landscaping. With its 22-inch laser-cut blades and ability to slice through branches up to 3/4-inch thick, it’s in a completely different performance class. It’s part of DEWALT’s 20V MAX battery ecosystem, making it a great choice for those already invested in the platform. However, it’s also much heavier, more expensive (and sold as a bare tool), and lacks the grass shear function. You would choose the DEWALT for maintaining large hedges and overgrown shrubs, not for delicate trimming around flower beds. The Sun Joe is the specialist for fine details; the DEWALT is the workhorse for bulk removal.

2. Makita XMU04ZX 18V LXT Cordless Grass Shear

The Makita XMU04ZX is a more direct competitor to the Sun Joe, offering a similar 2-in-1 grass shear and hedge trimmer functionality. Coming from Makita, a brand renowned for professional-grade tools, you can expect superior build quality, likely with more robust internal components and a higher price tag to match. It’s part of the extensive Makita 18V LXT system, a massive advantage for anyone who already owns Makita tools. The choice here comes down to budget and ecosystem. If you are a casual home gardener looking for an affordable solution for light tasks, the Sun Joe’s value is hard to beat. If you demand higher durability, plan for heavier use, or are already part of the Makita battery platform, the Makita is likely a worthwhile step up in investment.

3. WORKPRO 2-in-1 Cordless Grass Shear & Shrub Trimmer

The WORKPRO 2-in-1 is arguably the most direct, apples-to-apples competitor to the Sun Joe HJ604C. It features a nearly identical design philosophy: a 7.2V lithium-ion battery, interchangeable grass shear and shrubber blades, and a focus on lightweight, handheld operation. It’s positioned at a similar, highly competitive price point. When choosing between the Sun Joe and the WORKPRO, the decision will likely come down to subtle differences in ergonomics, specific blade lengths, and brand reputation. The WORKPRO boasts a slightly larger 2.0Ah battery, which may offer a longer runtime. This is the alternative for the buyer who wants to cross-shop the Sun Joe against its closest rival to see if minor feature differences or a current sale price sways their decision.

Final Verdict: Is the Sun Joe HJ604C Worth It?

After extensive testing and analysis, our verdict on the Sun Joe HJ604C Cordless Grass Shears Trimmer is a strong, but conditional, recommendation. For the right person, this tool is an absolute game-changer. If you are a gardener who obsesses over clean edges, needs a lightweight tool for shaping small shrubs, or has physical limitations that make heavier equipment a non-starter, this tool is a fantastic value. Its ease of use, precision cutting, and incredibly low weight make tedious garden chores genuinely enjoyable.

However, this recommendation comes with a critical caveat: you must respect its design limitations. The internal plastic gear is its Achilles’ heel, and attempting to cut material that is too thick or hard will lead to its premature demise. This is not a tool for clearing overgrowth or renovating a neglected hedge. It is a maintenance and finishing tool. If you understand and work within that boundary, you will be rewarded with years of service from a wonderfully handy and affordable device. For its intended purpose, it is one of the best and most accessible options available. If you’re ready to achieve those perfect garden edges with minimal effort, we highly recommend you check the latest price and see if it’s the right fit for your yard.