I have an illuminated park with pink and purple hybrids along with pink hydrangeas. As someone who's developed their entire town, I can help you with a few pointers.
Make sure your park location is exactly were you want it, and place down your main PWP. What color is the project? Think about complementary colors when you're choosing your flowers, bushes and trees. A cedar park is nice, but cedar trees only grow in the northern most area of town so be careful about what you plant. Choosing a single tree type or single fruit tree gives overall unity to your park. I have a pink park that's surrounded with peach trees, and it's very pleasing to the eyes!
Now consider your bushes. Bushes take a long time to collect and grow, so choose a single bush type and focus your efforts on collecting them. Be careful not to plant them too close to your PWP, and don't make a singular line of connecting bushes and trees longer than 12 spaces. (The 13th one won't grow.)
While you're collecting bushes, start the hybridization of flowers on your beach. I never ever stick two of the same types of flowers together because it looks too basic and monotonous to me. (Example, one area of my town has a white and yellow garden. White lilies, yellow tulips, white roses, yellow roses.) Use your imagination and plant flowers thoughtfully.
Lastly, add extras! Occasionally I'll set baskets of fruits, or lay patterns to give the area a well groomed feel. The more effort you put into your park, the better!
