The volatile nature of the markets over the past year demonstrates how difficult it is to time the market. If you bought stocks last January, you probably struggled, but if you bought in the summer, you are a hero. And that regardless of whether it was the same companies in each instance.

An alternative to trying to time the market (which even famed investor Warren Buffett says he can't do) is to buy high-quality growth companies with long-term growth prospects at any point in time and hold on to the stock long-term.

In that vein of thought, here are three growth stocks purchased by another famed investor, Cathie Wood of Ark Invest, through her investment firm's various Ark funds. All three are solid buy-and-hold candidates.

1. Honeywell International: An exceptional industrial stock

There is a conglomerate stock in the ARK Space Exploration & Innovation ETF (ARKX -2.55%) that has an intriguing mix of near-, medium-, and long-term growth prospects. In the near to medium term, its aerospace segment makes it a play on the commercial aerospace recovery. However, thinking longer term, Honeywell (HON -1.03%) is a key provider of avionics and propulsion systems to the nascent air taxi and cargo drone industry. Meanwhile, its Honeywell Building Technologies segment gives it exposure to the need for commercial building owners to ensure healthy, clean buildings; generate cost savings; and improve emissions by using digital technology in smart buildings. 

The third of Honeywell's four segments, performance materials and technologies (PMT), has near-term potential from its refining catalysts and environmentally friendly refrigerants, while its process solutions business will benefit from energy sector capital spending, including liquid natural gas investment. Longer term, Honeywell has a clutch of sustainable technology solutions, including renewable energy storage solutions, renewable fuels, and carbon capture technology. 

The final segment, safety and productivity solutions, is set for a revenue decline this year. Still, it's only a matter of time before spending on its e-commerce warehouse automation improves while its IoT sensing business grows. 

All told, Honeywell has plenty of near- and long-term growth businesses that guarantee long-term growth for investors. 

2. Ansys: Supercharged profit margins and strong growth prospects

Ansys (ANSS -1.25%) is a market-leading engineering simulation software company held in the ARK Space Exploration & Innovation ETF and in the ARK Autonomous Technology & Robotics ETF (ARKQ -2.44%). Ansys specializes in software that helps its customers simulate the behavior and qualities of its physical assets. For example, consider a Formula One team using Ansys software to simulate how a car performs aerodynamically on a track and then how the team will iteratively adjust the car's design accordingly. 

Given this example, it's easy to see that high technology tends to be the company's largest end market (up to a third of sales). Still, Ansys is also strong in aerospace and defense (19%) and automotive (19%), with other assorted industrial businesses contributing the rest.

The company's long-term growth is outstanding, and its 41% operating profit margin speaks to the strength of its market position. 

ANSS Chart

Data by YCharts

That said, Ansys isn't about to become a low-growth cash cow anytime soon, not least because of the growth of digital technology, notably digital twins (whereby a twin models a physical asset in the digital world) will only increase the value of its simulation solutions. The use of simulation can significantly reduce the time to market a product/technology and make research & development expenditure more productive. It all speaks to a great long-term future for the company.

3. PTC: A growth stock benefiting from the digital revolution

Speaking of digital twins and the digital revolution in the industrial sector, it's time to take a look at Ansys' partner, PTC (PTC 0.49%) -- held in Ark Invest's The 3D Printing ETF (PRNT -0.93%). The company is a leader in product life cycle management software (management of an asset from inception through to production, usage, and ultimately disposal) and a significant player in computer-aided design (CAD) software used to design the physical world.

Meanwhile, its fast-growing internet of things (IoT) segment helps connect the physical world to the digital world, and its augmented reality (AR) segment augments the physical world by allowing for the digital overlay of complex data -- think of a service technician using a tablet to "look" at process automation piping and valves.

Just like Ansys, PTC is a big winner from the trend toward digitization in the industrial world, and the two are natural partners -- PTC's software digitally connects the physical world, while Ansys' software simulates it and predicts outcomes. 

In addition, PTC has a growth driver from offering its solutions in the cloud -- a significant plus for customers interested in allowing multiple users to access the software online and better collaborate on a design or a project. 

As such, PTC's solutions are ideally placed to benefit from the digitization of the industrial world, and the stock remains attractive for long-term investors.