Here is the full list of all 47 Viridi achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Throw one hundred mature plants into the garden
Throw fifty mature plants into the garden
Throw ten mature plants into the garden
Flower a Senecio serpens
Flower a Senecio rowleyanus
Flower a Pachyphytum oviferum
Flower a Lithops optica 'Rubra'
Flower a Kalanchoe rotundifolia
Flower a Pachyphytum hookeri
Flower a Echeveria runyonii
Flower a Sempervivum
Flower a Fenestraria aurantiaca
Grow a Senecio serpens to maturity
Flower a Kalanchoe thrysiflora
Grow a Lithops optica 'Rubra' to maturity
Grow a Pachyphytum oviferum to maturity
Flower a Pachyphytum glutinicaule
Flower a Aloe 'Blue Elf'
Grow a Sempervivum to maturity
Grow an Echeveria runyonii to maturity
Grow a Senecio rowleyanus to maturity
Grow a Pachyphytum hookeri to maturity
Flower a Echeveria 'Lola'
Flower a Haworthia attenuata
Grow an Aloe 'Blue Elf' to maturity
Grow an Echeveria 'Lola' to maturity
Grow a Kalanchoe thrysiflora to maturity
Grow a Kalanchoe rotundifolia to maturity
Grow a Pachyphytum glutinicaule to maturity
Grow a Fenestraria aurantiaca to maturity
Flower a Cheiridopsis denticulata
Grow a Haworthia attenuata to maturity
Grow an Agave macroacantha to maturity
Grow a Cheiridopsis denticulata to maturity
Flower a Sedum morganianum
Flower a Sedum pachyphyllum
Grow an Agave 'Blue Glow' to maturity
Throw one mature plant into the garden
Flower a Aloe vera
Flower a Pachyphytum fittkaui
Flower a Echeveria glauca
Grow a Sedum pachyphyllum to maturity
Grow an Aeonium to maturity
Grow an Echeveria glauca to maturity
Grow a Pachyphytum fittkaui to maturity
Grow an Aloe vera to maturity
Grow a Sedum morganianum to maturity