Hi, I was trying Frans + MMM for the first time. So I started a new game and when I got out of the sewers the grass was all colourful, like hippie (although with less colours). I ran BOSS after installing Frans + MMM. Here's the BOSS log

Oblivion.esm  . Note:  Masterlist Information: $Revision: 788 $, $Date: 2010-04-02 12:04:08 -0700 (Fri, 02 Apr 2010) $, $LastChangedBy: pacificmorrowind $Francesco's Leveled Creatures-Items Mod.esm  . Bashed Patch tag suggestion:  {{BASH:Invent, Delev, Relev, Actors.AIData,Actors.Stats, Stats}}Francesco's Optional New Items Add-On.esmFrancesco's Optional New Creatures Add-On.esmMart's Monster Mod.esm  . Bashed Patch tag suggestion:  {{BASH:Actors.AIData,Actors.AIPackages,Actors.Stats,Delev,Factions,Graphics,Invent,Names,Relations,Relev,Scripts,Stats}}Unofficial Oblivion Patch.esp  . Note:  Recommend installing UOP hotfix for additional fixes: http://www.tesnexus.com/downloads/file.php?id=27710  . Bashed Patch tag suggestion:  {{BASH:Actors.AIData,Actors.AIPackages,Actors.CombatStyle,Actors.DeathItem,Actors.Stats,C.Climate,C.Light,C.Name,C.Owner,Creatures.Blood,Delev,Factions,Invent,Names,Relations,Relev,Scripts,Stats}} and remove the C.Water tag (only exist in older version).  . Note:  Remember to use the 'MOBS' version when using Francesco's or FCOM.  . Note:  Newest MOBS and non-MOBS versions have the same name.Francesco's Optional Files.esp  . Bashed Patch tag suggestion:  {{BASH:Delev,Relev}}Mart's Monster Mod for Fran.esp  . Bashed Patch tag suggestion:  {{BASH:Actors.AIData,Actors.AIPackages,Actors.Stats,Delev,Factions,Graphics,Invent,Names,Relations,Relev,Scripts,Stats}}Mart's Monster Mod - Diverse Imperial Armor.espMart's Monster Mod - Gems & Gem Dust.esp  . Note:  Will work with OOO 'light' but is not compatible with the 'full' installation of OOO. Should be fixed in future versions of OOO.Mart's Monster Mod - Hunting & Crafting.espMart's Monster Mod - Looting NPCs & Creatures.espMart's Monster Mod - Durability & Damage.espMart's Monster Mod - More Wilderness Life.esp  . Note:  Use either 'More Wilderness Life' or 'More Wilderness Life No Gates' but not both.Mart's Monster Mod - More Passive Wildlife.espFrancesco's Slower skills x1.5.espFrancesco's 10 days respawn time - 1-20 day lenght rescale.esp

MMM & Frans shouldn't have anything to do with grass.
Did you modify the oblivion.ini? In the grass section.

Do remove: Francesco's Optional New Creatures Add-On.esm
This is handled by MMM and will conflict.

By any chance does the grass look like a mini-map of Cyrodiil? If so, your shaders are messed up, you'll need to replace them. I believe you can download them from the Nexus.

Noticed it looks like the map. I can see the imperial city in it lol.

I downloaded the shaders from nexus and it works now Thanks alot!

Yep, that's your shaders being messed up. You'll need to replace them with the default ones. IIRC, someone uploaded them to the Nexus because of this very problem that people were having.