In many cases, such gardens are vast - made up of many hectares of lawns, woodlands, colourful borders, kitchen/walled gardens and glasshouses.
The head gardener is also often in charge of several under gardeners who help with the busy seasonal schedule. They might also have to design and plant new areas and features of the garden.
What is best about being a head gardener for a private estate?
"It's a very creative job," says Beverley Aspinall, owner of Oxnead Hall Estate in Norfolk. "You have to have a real visual impression of where you are taking the garden in the long term as well as the short term." Viscount Ashbrook, owner of Arley Hall in Cheshire and patron of the Professional Gardeners' Guild, points out that some private estate owners leave a huge amount of work and responsibility to the head gardener. "Some head gardeners like that kind of arrangement. They love the freedom and feeling of authority that gives them. But at Arley we are not like that at all. My wife and I take a close interest in what's going on in the garden and we are very involved in the garden. We have always worked with the head gardener. It's a sort of partnership, and that's rewarding too."
What kind of skills, attributes, knowledge and experience do you feel are most in demand for this role in the recruitment market at the moment - and why?
Practical horticultural knowledge
"Above all, you need horticultural knowledge," Aspinall maintains. "It's something that has to be learned. You have to show employers that you have a combination of academic and practical experience. Learning the name of a thousand plants does not come by just doing nothing. You have to apply yourself to it and then understand what to do with all of those plants, so horticultural knowledge and experience is absolutely critical."
"Gardening is a very long-term activity," Aspinall explains. "Something that you plant this year you might not see flower for another three or four years."
Design and planning skills
Aspinall points out that a head gardener also needs to understand design at all levels - from planting an avenue or renovating a woodland to deciding which plants go in which position in a border. "You need an understanding of design for those types of jobs," she says.
Ashbrook explains that head gardeners often have to direct several under gardeners. "The head gardener has also got to be able to relate to the owners, so they have got to be flexible," he says. Aspinall adds: "You have to be able to manage other people - and we, the owners, have ideas of what we want to do so the head gardener has to liaise with us too and interpret that in their own way and communicate that to their team to achieve that." She explains that what separates a head gardener from an under gardener is that they need to adopt a "management view" of the garden. For example, the head gardener is managing the garden's seasonal cycle - assessing what they need to do at different times of the year. The head gardener is also managing the team to accomplish jobs for the long, medium and short term.
Ashbrook suggests that it is "very helpful if you can make a garden plan on the computer". Aspinall adds: "You need spreadsheets to keep track of all of the activity in the garden every week so we know exactly what's happening and who's doing what. It also helps to keep a record of what works and what doesn't work in the garden."
Ancillary/health and safety skills
According to Aspinall, head gardeners carry out and manage lots of ancillary skills such as mowing lawns. For this reason, they need to be able to safely operate heavy machinery such as mowers and strimmers. "It goes with the job," she says.
What sort of qualifications and experience would you need to see from a potential candidate to be convinced that they possess these qualities?
Both Aspinall and Ashbrook say there is no rigid requirement, rather the level of experience and formal qualifications needed to be a head gardener depend on the size and type of the garden. Ashbrook says: "If it's an important garden with good collections of plants and a big range of plant material, the more qualifications the better. For example, a head gardener at Exbury Gardens, which is full of ericaceous plants, would be an expert in that field." He adds this his current head gardener has the equivalent to a degree in horticulture and that in the past he has employed a head gardener with a Kew diploma, which he describes as a "high-quality" qualification, as are the RHS qualifications. Aspinall says: "It's not as straightforward as doing A levels and then gaining a degree. What I look for is evidence of some sort of academic qualification - whether that's an RHS qualification or not is not as important to me." She adds: "Our garden is 15 acres so a head gardener would need a wide range of knowledge, from woodlands to herbaceous borders and greenhouses. We would say that 10 years as a gardener and three or four years as a head gardener is the minimum we are looking for."
Are any of the skills that are in demand transferable from other horticulture roles?
Ashbrook says: "Yes, I am sure you could move to the role of head gardener from other horticulture roles. It's all gardening, whether you are growing roses on a private garden or on a corporate site, and people do transfer from one to the other." Aspinall adds: "Yes, all of those types of skills would be transferable from other types of roles. The only difference is the upward management. Equally, going the other way, having been a head gardener for a private estate there are all sorts of other roles you can get into."