When we visited Benmore Botanic Gardens couple of days ago, rhododendrons were in bloom. Even without them, gardens would be great, but it was a big bonus. I definitely recommend a visit, if you are on Cowal. They are a little bit more expensive than Cambridge ones - £10 for family ticket against £8 for two adults - but then again, the parking is free at Benmore, they are a lot bigger, more varied and have a lot better setting.
The only problem with them I see is that only part of the gardens is accessible for wheelchair users - the level one close to the river. Large portion of the grounds is one big steepish slope with many stairs and a viewpoint at the top
Since I didn't get rid of my old camera yet, I took it with me. I don't like changing lenses alfresco, there's always a chance that something sticky gets onto the sensor, so I used another camera instead. Lens that I had was my underused lensbaby. What I did forget to take were changeable aperture rings for it, and the one I had was large-opening 4, so the sweetspot is small and "fly-in" effect rather dramatic. Life like bumblebee must see it
Redwood avenue was very impressive. I don't know if it's not allowed to walk there ever or just temporary, but it was impressive even without spoiling the nice lawn.
One more thing. Little touristy "freehand-drawing" map of Cowal, that you pick at tourist info places or in hotels, has a mistake on it - the entrance to the garden is shown on a smaller road that branches off A815. It is actually on A815 itself. If you are coming from Loch Fyne - Loch Eck direction, it doesn't matter, you will pass the entrance. If you are coming from Dunoon, just carry on along A815. I think the mistake was introduced because two roads are physically very close together.
spring blossoms on shutterstock