The bulk of your planting should be done right now.
Start containers in mid-May and then harden them off by bringing them in and out of the house. For larger containers I would recommend that they be planted at this time.
If you are dealing with new introductions, they have been bred to work hand in hand with fertilizing. They are voracious eaters and the only way that you will be able to get your plants looking like they do in the catalogue picture is to fertilize. For my flowerbeds, I use a lot of organic matter in the soil and extra manure, plus I use a liquid fertilizer every two weeks. For pots, you should be using a soilless mix (a potting mix). Garden soil expands and contracts during the winter and can crack your ceramic pots. Annuals add colour and variety to the look of the garden and bring continual change.
The soil temperature has warmed up enough that the bacteria in the soil has become active and
starts breaking down the organic matter in the soil.
Pine candles are also extending now and you only have the next two weeks to break the candles.
The proper way to trim pines, example Mugo Pine, is not to hedge them in July like you would do with other shrubs but rather to break the candles now. You will see a thin little finger beginning to extend from the top of the pine and this finger represents the entire growth for the year. If you break the candle in half you will reduce the growth of the pine by half for the year. If you don’t want any growth for the year then you would break the candle off completely.