pros

nice ult
good peel with snare and plants
good burst if use of correct combo
long range basic

cons

very squishy
slow movement speed
skill to land snares and combo plants snare and seeds at once
positioning to not get blown up in team fights

The new support changes in the preseason has given the chance for supports to get more money and actually change from a supportive no damage warding champions to warding but also damage champions that can dish out some nice damage and offer more for the team.

relic shield nerfed so now go Spellthief's Edge to Frostfang don't upgrade to Frost Queen's Claim early since its not that useful

my opinion of most efficient masteries. The mastreies put in utility are core but then you put into defense if you want to.

snare is most useful so max first then its your choice to put into q or seeds(e) but i prefer to max q then finish seeds off last. Also don't forget to upgrade ult whenever you can

her combo is snare into seed then ult then put other seed with q
or
ew-r-qw

basically snare with seed then ult, put another plant for the ult buff

will put more details if people like it or it get a little popular

items depend on different situation but sightstone ,spell thief, Liandry's Torment and then you can customize but i put in the ones that for me are the most efficient and effective.