This card is treated as a Normal Monster while face-up on the field or in the Graveyard. While this card is face-up on the field, you can Normal Summon it to have it be treated as an Effect Monster with this effect:● Once per turn, you can Special Summon 1 Insect-Type or Plant-Type monster from your hand or Graveyard.
Since it's treated as a normal monster, you can use Birthright or Soul Resurrection to special summon it from the graveyard. Dust Knight is used to search for it from your deck to the grave, allowing you to potentially special summon him early.
Gigaplant is best used in a plant type monsters since there aren't other plant type gemini available, but it's still worth noting that gemini support cards help speed up the process to get their effects up. Using Supervise can essentially protect it, and Superalloy lets you use Gigaplant's effect right away. Gemini Trap Hole can be a dead hand if you don't use plenty of gemini monsters, but good in certain situations.
Blazewing Butterfly, Double Summon/Super Double Summon & Swing of Memories
Using the effect of Blazewing Butterfly can help you to special summon Gigaplant from your graveyard to your Field, you can also use Double Summon or Super Double Summon to speed up Blazewing Butterfly’s effect.
Swing of Memories can also help you to Special summon this card from the Graveyard for 1 turn.