The garden was created around 1770 by Sir John Campbell who resided at Stackpole Court which was demolished in 1963
First evidence of the walled gardens can be seen in the Estate plan of 1782 which clearly shows a D shaped garden with the same perimeter as it has today but without the central dividing wall. In 1791 the gardener had a staff of 14 men and 4 women and they produced plants and produce for use on the Stackpole Estate.
By 1818 an internal dividing hot wall had been added that effectively divided the garden in half. A classic arch allowed access between the sections along with 2 Regency style pavilions which each contained a lower room partially below ground. These lower rooms contain brick vaulted ceilings, cobbled floors and house fireplaces feeding flues in the dividing wall. Above, there are square rooms with concrete floors. These are roughly the location of seed rooms recorded in sketches of 1825.By this time two additional gardens constructed in stone had been added to the east producing the layout that we can see today.
Sometime after 1815 an underground boiler house was constructed and equipped with coal fired boilers, the flues of which were concealed in the stone walls. The hot pipes ran under several forcing pits which were used to grow melons. The boiler house is now a haven for several species of bat, including the Greater Horseshoe, and is now a designated a site of special scientific interest.
By 1875 hot houses had been added to the southern face of the dividing wall behind the western pavilion. On the south wall of the largest section of the garden were 8,000 Sq Ft of glasshouses, primarily used as vineries. You can still see the remains of the tying system, pineapple beds and ventilation. The roof water from the glasshouses was collected in two reservoirs, one of which remains today.
Following the demolition of Stackpole Court the garden was successfully worked as a market garden for a number of years by a local family who unfortunately had their tenure terminated when Lord Cawdor had, thankfully unsuccessfully, plans to use the site as a holiday camp.
A large proportion of the Stackpole Estate, including the walled garden, passed into the hands of the National Trust in 1976
In 1983 the Haverfordwest and Area Society for Mentally Handicapped Children and Adults leased 3.3 acres of the garden from the National Trust with the aim of providing meaningful work experience for local adults with a learning disability. It had been disused for a number of years and was found to be in a severe state of neglect. None of the glasshouses had survived. Much hard work ensued to restore it to a cultivable condition.
The arch had been closed many years previously and the Southern section was being used by another project as a sensory garden, but this too had fallen into disuse and was a wilderness before the Society took it on board
In 2002 the National Trust reopened the arch and the Society renegotiated the lease of the garden for a further 40 years taking the site back to its original size of almost 6 acres.
In 2008 the Haverfordwest and Area Society for Mentally Handicapped Children and Adults changed its name to Pembrokeshire Mencap (Reg Charity No. 1128982) and it continues to provide a valuable service in Pembrokeshire for approximately 30 people with learning disabilities.
The Garden continues to produce food for the table and hopefully will continue to do so for the next 250 years.