At the beginning it's important to get some basic experience with caring for plants. As soon as you have raised 3 plants in your own garden (those gifted to you by other players don't count), you will be rewarded with getting an access to the Atrium. You can decorate the Atrium with adult plants according to your own taste, create seasonal designs etc.

There is no limit for the number of adult flowers and sprouts one can have. However, there is a limit for the number of seeds: three at a time.

At present, the seeds delivered by the post pixie use additional seed slots. This is going to change in the future. It will be possible to have an unlimited number of parcels with special seeds. As soon as the parcel is unwrapped, it will disappear; the seeds will be stored separately, awaiting a free seed slot (flowerpot).

Seeds can be gifted, but in order to accept the gift, the giftee must have fewer than 3 own seeds.

No. Plants cannot die at any stage of their development.

Note: In the past, mature plants could wither (get limp) if they had no water and the Sun was completely covered by clouds. Limp flowers died after 14 days if they didn't get any sun and water in the meantime. In order to prevent withering, the flowers could be planted in the garden. Then they were automatically provided with enough water.
Reference: News - Flowergame

At present, each adult plant gets light and water on its own.
Reference: News - Flowergame

Seeds and sprouts stop growing when they have completely no light or water. As soon as they are provided with a little light and water, they resume their growth. Depending on these amounts, they can develop very slowly or very fast. The development is fastest with maximum water (5 drops) and full sunlight.
Reference: News - Flowergame

The Compendium shows all the development stages and color variants you have or ever had in your Garden. Any new plant you get appears there immediately and is never deleted, even if you abandon or gift it and you have no other plant of this kind. The Compendium doesn't show you your current flower collection; it rather reflects the state of your knowledge and shows you what plants you are still missing.

The color of parent plants doesn't matter. The color of the offspring is randomly selected by the system the moment your plant grows up. In order to get a specific color variant, you should just breed flowers of this species as often as possible until you are lucky. It can be helpful to check for trade offers on the Forum, or even to start your own trading thread. Swapping is usually easier than getting the desired color variant on your own.

Nothing is wrong with your plants, they only need a little time. You must wait 7 days after each breeding for the "Breed" option to reappear. Then your plants are ready to breed again. If you have no "Breed" option on the flower's page, it means you either bred it yourself in the last seven days or you were given a plant that was bred recently by its previous owner.

The Christmas season may have already started in real life, but in Flowergame it usually begins right before the holidays. Follow the News section on the forum and watch out for an announcement.

When you go to the flower's page, you will find three boxes with codes. The first box contains Gift URL. Paste it into a PM or an e-mail, or post it on the forum. Please note that gift URLs posted on the forum can be claimed by anyone, so if your flower is meant for a specific player, you should use PM or e-mail instead.

Only two things are important: you shouldn't go back, and you should be in the top row when you finish the game. There can be many possible starting points and paths to the goal.

Well, there are actually no tricks as such, but you can learn some useful methods. Some tasks are very easy and can be used to practise. On the other hand, the most difficult tasks sometimes require a little "tricky" thinking. Try looking for the way both from the top and from the bottom. Obviously, some ways will turn out to be blind alleys and then you have to go a little back and look for a better way. In some respects, the Pipe-game is very similar to a maze. Sometimes the way is very simple and direct; sometimes it's very indirect and complicated. You win the game when you connect the last two pipes and the water can flow from the half-buried pipe at the top to the the sprinkler at the bottom. Don't give up: with some practice you will make a good plumber!