'Gosh, I’ve never seen a heather that big.”

We had just arrived at RHS Harlow Carr, when my husband spotted a monster heather – a magnificent spray of purple, far taller and thicker than anything we had ever come across on the Yorkshire moors.

Its Latin, or botanical, name – superba erica arigena – summed it up nicely. A moment later and something else caught his eye – an apple hedge. “I’ve never seen apple grown as a hedge before,” he said, going up close to study it.

Whether you’re Alan Titchmarsh or an absolute beginner, you are bound to learn something on a visit to Harlow Carr.

I knew my husband would love it. I had been before to the attraction, set in a valley on the outskirts of Harrogate, but he hadn’t, and as a keen gardener, I knew he would be inspired by the variety of plants and trees.

What I like about the garden, and what I remembered about it, is the way the planting schemes gel perfectly with the surrounding landscape. Woodland, ponds, a stream, rock gardens, flower borders and mown grassland are full of seasonal colour and fit snugly into the rural setting.

Daffodils – or narcissus to give them their botanical name – were out in abundance, dancing in the breeze. Like every other plant in the garden, they are named, enabling visitors to jot them down and buy them later. Peeping Tom, Little Witch, every variety was different.

It was a chilly day so, battling the breeze on the valley sides, we wandered into the alpine house, a large glasshouse in the garden’s alpine zone. I’m not a fan of alpines or low-ground cover plants in general, but I quickly became a convert. The little plants were meticulously arranged to give an overall look that I found calming and beautiful. The pint-sized flowers and foliage, nestling in sand and gravel, reminded me of the miniature garden-on-a-plate arrangements I used to make as a child to enter local shows.

I liked some of the alpines so much I made a note to look in Harlow Carr’s plant centre before going home.

We moved on to the scented garden where we sat and savoured the almost overpowering perfume from spectacular clumps of blue hyacinths. Nearby, young children watched as hens pecked about in a cosy-looking run. Information boards beside the run offer tips on keeping chickens.

Covering 68 acres, the garden has a unique topography and varied growing conditions that challenge its team of gardeners. The site experiences cold, dry winter winds, frequent deep frosts and a relatively short and cool growing season with some wet weather thrown in. The garden, which has acidic soil in some areas, stands at an altitude of 155m (508ft) above sea level. These combined conditions result in a different range of plants from other RHS gardens across the country.

Dropping to the valley floor, we strolled along wide, easy-to-negotiate footpaths. The garden is accessible to wheelchair users, and hires out wheelchairs and mobility vehicles.

When crossing the stream that flows the length of Harlow Carr, we noticed a distinct smell of sulphur and a cloudiness in the water. The garden owes its existence to mineral springs in and around Harrogate, which were first discovered in 1571. In 1734, one of the springs on the Harlow Car Estate, as it was then spelled, was found to be sulphurous and considered to have health benefits. But it was many years before the site was developed as a spa. In 1840, Henry Wright, the owner of the estate, cleaned out and protected one of the wells and, four years later, built a hotel and bath house, also laying out pleasure gardens.

In 1861, Harlow Car Springs was described as a ‘sweet, secluded spot... The grounds are neatly laid out, adorned with a selection of trees, shrubs and flowers, walks, easy seats and shady arbours.’ Just as it is today.

Much later, the site was taken over by the then Northern Horticultural Society as a northern counterpart to the RHS garden at Wisley in Surrey, where new plants could be tested for hardiness and suitability to northern climes. In 1950, Harlow Carr Botanical Gardens opened to the public.

As we walked, the streamside show of plants was lovely, with bright yellow marsh marigolds along the water’s edge, and a weird-looking plant – yellow with a dish-like head – dotting the banks. “It looks like something out of Dr Who,” we remarked. This area is at its best, we were told, from April to autumn, when the banks are covered in a lush carpet of flowers and foliage.

The garden is full of contrasts. Leaving the valley floor we climbed a slight gradient to the woodland, where the excited squeals of children could be heard enjoying an imaginatively-designed adventure playground, complete with tree house. Other highlights for children include the log ness monster, built out of birch and oak logs and a log maze.

Breaks in the trees open up the forest floor for plants such as bluebells and rhododendrons, which are a magnificent sight in late spring and summer.

We walked to the lake, where moorhens darted between stones, and passed the Bramall Learning Centre, one of the greenest buildings in the country. Here, around 10,000 children come each year to learn about gardening and plants.

Before leaving, we popped to the plant centre where, after chatting to one of the many helpful members of staff, I found my alpines and bought a pot to plant at home.

We had a great afternoon, and know that if we visit again in a couple of months, the garden will look different again.

Factfile

  • RHS Harlow Carr is on Crag Lane, off Otley Road, Harrogate.
  • The garden is open all years except Christmas Day. Until November 8 it open from 9.30am to 6pm. Last admission is an hour before closing.
  • A Plant Heritage Spring Plant Fair will be held tomorrow from 10am to 4pm, and on May 10 and 11 a rhododendron show will take place.
  • For more information and prices, ring 0845 265 8070, call rhs.org.uk/Harlow-Carr-Garden, or e-mail harlowcarr@rhs.org.uk.