She probably died shortly after the 1636 birth of her last child.
From The American Genealogist, volume 30 (1953), p 156:
"The surname Friar appears to have been first stated in print by the Rev. Joseph B. Felt, well over a century ago. Neither Dr. Gardner nor Mr. Moriarty was ever successful in finding Mr. Felt's evidence; but it would be well not to reject the possibility that Friar (or a variant) is right until we can either prove that the true name was something else or explain how the error arose."
And even if her maiden name was Friar (of whatever spelling variant), there is no documentation of her parents. Possibilities that need confirmation through solid documentation include:
"B. Margaret Friar: This is the name many times stated to have been that of that earlier wife of Thomas(1) Gardner whose existence is demonstrable from the allusion in his will, dated 7 Dec. 1668, probated 29 March 1675 [Essex Wills, file 301:62: Probate Records, 2:423], to his then wife Damaris, "mother-in-law" of the sons. Damaris was the Widdow Shattock who joined First Church, Salem, 2 July 1641. When the earlier wife died and the second marriage took place are unknown, but Damaris died on 28 Nov 1674, a month before Thomas(1) Gardner died in 29 Dec 1675. Thomas(1) Gardner's name appears fifteenth on the covenant of First Church, signed 6 of 6th month 1629, and a woman named Margaret Gardener is the next member of the family to join on "1639-24-1" [24 Mar 1639/40?]. On "15-10" in the same year, in any case later than the date of Margaret's admission, the name of Tho. Gardener Junyr appears. Though he was by this year certainly old enough to be married, and it is possible that Margaret was his wife, the baptisms of his children do not start until 28 Jan. 1643/4, so I am inclined to agree with Dr. Gardner and Mr. Moriarty that Margaret was actually the name of the earlier wife of Thomas(1) Gardner."
↑ Dorset History Centre; Dorchester, England; Dorset Parish Registers. 1598 June 25 Margaret Friar bapts (Ancestry has her indexed for some reason as Margaret Lalane)
↑ Dorset History Centre; Dorchester, England; Dorset Parish Registers; Sherborne combined register, Reference: PE/SH:RE1/1: 1617: 28 Thomas Gardiner et Margarete Frier nuptia
The American Genealogist, volume 30 (1953), p 156
Robert Charles Anderson, Great Migration Begins...," Boston, MA: NEHGS 1995
"Pedigree Resource File," database, FamilySearch (https://familysearch.org/ark:/61903/2:2:943B-S7M : accessed 16 October 2018), entry for Margaret Fryer; file (2:2:2:MM9R-SW5), submitted 19 June 2003 by rwylie2770211 [identity withheld for privacy].
Also, see Edit Notes at Thomas Gardner. As well, we will expand this Edit Notes section for Margaret as we go along. This section will disappear after Profile work is accomplished. However, we will have notes appended to Research Notes with respect to pending research and updates.
Starting with proposed parents for Margaret - Marriage of Walter Friar and Grace Mullins. His will (1610) mentions Margaret among his children. This was before the Gardner marriage (unfortunately). However, someone saw the Thomas and Margaret connection 200 years ago (which New England researchers heard about).
See Sherborne focus page for a list of the images (currently, snips/snaps, soon the whole image) that will support the coming changes.
Like we will do with respect to pending changes at the Thomas Gardner page, we will itemize pending changes here.
For each of those snaps on the right side (above) that were taken from images at Sherborne's repository, there is the full picture. These were retrieved from ancestry.com (we need to get the reference address). My ancestry account does not, currently, have access to their images (will turn it on - unless someone looks for these and gets the URL). We do not want to make a copy here.