The Princess of Wales planted Sweet William seeds, prompting a chuckle from her husband, as the pair toured the plot of a new therapy garden on an away day to Wales.

Kate and the Prince of Wales visited Brynawel Rehabilitation Centre near Pontyclun on Tuesday to mark their charitable foundation’s new collaboration to help create allotments to support mental health.

William laughed as he spotted the name of the flowers – “The Sweet William” – on a label, as volunteer gardener Vanessa Townsend helped Kate sow the seeds, telling her: “They will flower in two years. I’ll make sure you get some.”

The couple, wearing daffodils pins in their lapels, were carrying out a host of engagements across south Wales, the day before St David’s Day, which celebrates the patron saint of Wales.

Kate was presented with a bunch of daffodils by two-year-old Cora Phillips.

Cora’s mother Michelle Phillips, from Llanharan, said: “Oh my goodness, I did not expect that in a million years.”

Turning to her daughter, she said: “We just met a princess. We’re never going to forget that.”

Ms Phillips said they lived nearby and had bought daffodils ahead of St David’s Day.

The prince and princess were also greeted by a therapy dog, seven-year-old Great Dane, Ragnar.

Stroking Ragnar, William commented on the dog’s “big ears”, while Kate said: “He must be very popular.”

William was asked several times about the rugby union match they attended on Saturday.

The prince and princess were in the stands for England’s victory over Wales in the Six Nations at the Principality Stadium in Cardiff.

William is patron of the Welsh Rugby Union, while Kate is patron of the Rugby Football Union – having taken over the role from the Duke of Sussex a year ago.

Asked if he enjoyed the game, William joked: “Not really.”

He later told volunteers: “I’ve had non-stop grief about it all weekend.”

Kate was dressed in a long cream coat, white polo neck and a long black and white houndstooth skirt, paired with black boots, while William wore a smart long navy overcoat, pale blue shirt and navy tie.

The Royal Foundation of the Prince and Princess of Wales has announced it is working with Life at No.27 – a horticultural therapy and mental health counselling provider – to scale up its gardening mission, with six gardens eventually being created across south Wales.

William and Kate were shown plans for the Brynawel garden which includes a collection of allotments where individuals can have their own space to learn and grow produce, a communal sensory and herbal garden, a mud kitchen and an interactive learning space.

The Brynawel Rehabilitation Centre – a leading residential site for the treatment of alcohol and drug dependencies – will offer free and low-cost gardening therapy and mental health support sessions for its service users and their families.

Residents from the wider community, who are experiencing mental ill health, low confidence or isolation, will also eventually be given access to the garden through GP referrals.

The Royal Foundation has brought together national and local organisations to support the design and build, and provide funding, tools, plants, seeds and materials for landscaping.

It said the initiative was part of a series of projects designed to leave a “lasting impact” in the communities William and Kate visit on royal engagements.

William was given the title the Prince of Wales by his father, the King, shortly after Charles acceded to the throne.