Oxford - city of spires ... and 8,000 flowers

The beginning of autumn is a perfect time to see England's glorious gardens, especially if the sun is shining (which it was today... oh what a miracle after all our rain!). And this week my travels took me to Oxford where I saw one of the most impressive botanical gardens I've seen anywhere in the world. It is also the oldest in Britain.

This is the University of Oxford Botanic Garden, set in the heart of the city near Magdalen Bridge, with the River Cherwell forming one of its boundaries. There are few vistas that don't include the wonderful old buildings, churches and spires that are synonymous with this great city of learning and the entrance is through a magnificent archway designed by Nicholas Stone (below).

This garden was founded in 1632 by Sir Henry Danvers, the Earl of Danby, but so much was spent on the walls and arches that make such a stunning backdrop to the huge plant collection that little was left for the running of the garden and the first curator - Jacob Bobart - was reputed to have worked for seven years without payment! He was forced to make ends meet by selling the fruit and vegetables he grew there.

This garden only covers 4.5 acres, but is packed with some 8,000 species representing 90 percent of families of flowering plants. It was originally established as a Physic Garden, so the main area is walled, and now divided into immaculately planted "Botanical Family Borders" which effectively display the vast range of species represented here. It is also home to the National euphorbia collection (well over 100 species) and you will see cultivars here that you didn't even know existed!

There is also a group of "economic" beds featuring plants used for medicinal and culinary purposes. And perhaps the most stunning and diverse plant displays are evident in the "Geographic" borders, which hug the walls of the garden, with plants grouped by country and including species from South Africa, South America, Australia and the Mediterranean.

Not to be missed are the glass houses, filled with more collections of exotic plants - cacti and succulents, a tropical palm house, fernery and fantastic collection of giant water lilies with their huge platter-like leaves and incredible patterns.

This is an amazing garden, hidden from the hustle and bustle of this academic centre of excellence, where you can spend hours marvelling at plants that you won't see elsewhere in England. It's open throughout the year and if you're in Oxford, make the effort to see some of the college gardens too - notably Trinity, Worcester, St John's and Wadham, which are all Grade II listed. And there is also the Harcourt Arboretum on the edge of the city, which is run by the Oxford University Botanic Garden.

But for me the most splendid display was the sunflowers - rising majestically from the ground to a huge height - with their huge heads swaying in the breeze - but also reds and oranges! The sight of them lifted my heart even further than all the other incredible plants that I had already seen.