Gardeners' World has lost its regular 8.30pm slot on BBC 2 to the semi–finals of the World Snooker Championship being played in Sheffield.
The gardening programme recently attracted 2.59 million viewers, its highest audience for six years.
But viewers are complaining that the show gives way each year to snooker in May and wall-to-wall Wimbledon tennis coverage in June and July.
Don took to Twitter and branded the snooker coverage a "crazy hiatus bound to annoy" his audience. He added: "And me."
Don added: "Total lack of interest in programme or audience by schedulers."
Viewer Bryan Appleyard tweeted: "They should be made aware that the whole point of a show like GW is continuity
Don replied: "Exactly…But few if anyone in BBC management understands that. Can’t see football being randomly dropped."
Viewers also want to see Gardeners’ World extended beyond half an hour.
Roz Smith tweeted: "Why isn't GW longer? At least an hour. Why does snooker…any sport ALWAYS take precedence over GW?"
In reply, Don tweeted: "Because they are cheap."
Smith replied: "Maybe the audience would increase if the BBC put on a series (preferably every week of the year).
"And then when snooker came on, they put it on another channel and left GW ALONE??"
When she said she wanted to see more BBC specialist gardening programmes, Don said: "I am afraid the chances of this are low. GW is currently seen as more or less fulfilling the gardening remit."
Smith then asked: "Who at the BBC ‘decides’ more or less that GW is enough for us all as Monty says?"
When Don tweeted that the process involves personal pitches to programme commissioners, she asked: "Can't we persuade them they are wrong?"
Don answered: "Good luck to you. I don’t seem to be able to."
And former Gardeners’ World presenter Toby Buckland tweeted his support to viewers, saying: "Write a letter to the Beeb saying what you want to see - tweets are too easily ignored. Good luck!"
Gardeners’ World will also be off air for three weeks – 28 June; 5 July and 12 July 2013 for Wimbledon.
A BBC representative said: "Gardeners’ World is broadcast across the year breaking only for major events. The transmission of sporting events is dependent on their dates so it is therefore necessary to move all types of programming, not just of the gardening type, around in the schedule and this is done with minimum disruption."