Saruman in the Shire: how long had he been planning it?

Question

I am trying to understand the actions of Saruman in the Shire. I will refer to the chronology of Appendix B of the Return of the King. All dates are relative to the Third Age.

Frodo leaves Bag End on September 23rd of 3018. Isengard is conquered on the 3rd of March 3019. At this time Saruman already had some interactions with the Shire, since he was "dearly buying" pipe weed and so on. But when had he begun? Gandalf had been imprisoned in Orthanc in July 3018: at that point if I'm not mistaken (but surely you'll know better) Saruman understands that the One Ring was hidden in the Shire and accuses Gandalf of having kept the news for himself.

Treebeard lets Saruman and Gríma free and the Hobbits meet the two, apparently wandering without much intent, on August 28th 3019. Now "Saruman turns toward the Shire" and will arrive there on Bilbo's 129 birthday, 22 September 3019.

On October 28th they arrive in Bree and it is already a very deeply changed Shire, with terror enforced by the Shirrifs, felled trees, broken mills and so on. Saruman has been scourging the Shire. Then the revolution begins and all's well that ends well (ok, almost...).

Saruman is surely powerful enough, given time enough, to arrange such a plot. But without his staff only his "poisonous speech" is left, he is weakened (so much that he is vulnerable to Gríma, something which is really strange given that to kill Gandalf a Balrog was needed, and Saruman at his full power was surely more powerful than Gandalf the Grey): clearly the speech is enough to corrupt men and hobbits alike, if it had been able to persuade an Ent, but still it's not much.

So, aren't the timings a bit too short? If Saruman had not know with proper advance about the real importance of the Shire, how could he so quickly set up his webs of treason and corruption, and then in less than a month completely "change" the mood of the Shire itself?

It almost seems that Saruman had been plotting against the Shire for a long time. Have I missed/confused passages and dates?

UPDATE: see this discussion on meta.

Answer 1

Saruman had been positioning himself in the Shire for quite some time, at least a couple of years and potentially as long as a decade or two. This is foreshadowed during the fall of Isengard in the Two Towers:

‘We understand it all perfectly now,’ said Gimli.

‘All except one thing,’ said Aragorn: ‘leaf from the Southfarthing in Isengard. The more I consider it, the more curious I find it. I have never been in Isengard, but I have journeyed in this land, and I know well the empty countries that lie between Rohan and the Shire. Neither goods nor folk have passed that way for many a long year, not openly. Saruman had secret dealings with someone in the Shire, I guess. Wormtongues may be found in other houses than King Théoden’s. Was there a date on the barrels?’

‘Yes,’ said Pippin. ‘It was the 1417 crop, that is last year’s; no, the year before, of course, now: a good year.’

‘Ah well, whatever evil was afoot is over now, I hope; or else it is beyond our reach at present,’ said Aragorn. ‘Yet I think I shall mention it to Gandalf, small matter though it may seem among his great affairs.’

Saruman had had quite a long relationship with someone in the Shire, who supplied him with pipeweed.

We also have two dates which show Saruman becoming aware of the Shire having a special significance, from Appendix B:

2953 Last meeting of the White Council. They debate the Rings. Saruman feigns that he has discovered that the One Ring has passed down Anduin to the Sea. Saruman withdraws to Isengard, which he takes as his own, and fortifies it. Being jealous and afraid of Gandalf he sets spies to watch all his movements; and notes his interest in the Shire. He soon begins to keep agents in Bree and the Southfarthing.

(...)

c.3000 The shadow of Mordor lengthens. Saruman dares to use the palantír of Orthanc, but becomes ensnared by Sauron, who has the Ithil Stone. He becomes a traitor to the Council. His spies report that the Shire is being closely guarded by the Rangers.

Saruman has been aware of the Shire for about 60 years (and got reports from at least 17-18 years), and has been obtaining pipeweed from it for at least two. As a result you can conclude that Saruman did already have his webs of treason and corruption in the Shire well before the Hobbits even left the Shire. After all, they noted Big People (Men) causing trouble as they were leaving the Shire in the Fellowship of the Ring:

‘But what has one of the Big People got to do with us?’ said Pippin. ‘And what is he doing in this part of the world?’

‘There are some Men about,’ said Frodo. ‘Down in the Southfarthing they have had trouble with Big People, I believe. But I have never heard of anything like this rider. I wonder where he comes from.’

There's no explicit link between these Men and Saruman, but as you say, he would have had to have his heavies relatively close by and large in number to enforce his martial law. Not all of them would have come down from Bree.

Answer 2

You are forgetting Lotho Sackville-Baggins. Lotho had been buying up a lot of the Shire, presumably using, in part, funds from sales to Saruman. He then started to throw his weight about, seeking to be a power in The Shire.

So Saruman is taking over an existing operation, rather than creating one from scratch

Answer 3

At the back of his mind for a while no doubt. He was dependent on The Shire for his secret use of pipe-weed. I guess he also accepted the local consensus it was of better quality than Bree-produce. The head of the Order of Wizards must have the best! ;)