Some 26,000 tulips on the royal wedding route down the Mall were due to be cut back in the run-up to the event because the weather had forced them to wilt.
A Royal Parks representative said: "We will deadhead the tulips before the wedding because they won't be at their best because of the heat." Lining the Mall instead will be the remaining 29,000 wall flowers and other plants.
The spokesman added: "The Memorial Gardens opposite Buckingham Palace look stunning and we will do our utmost to ensure they continue to look as good as possible in the run-up to the royal wedding.
"The recent warm weather may have caused the tulips to bloom earlier than anticipated, but the wallflowers and forget-me-nots will continue to look beautiful throughout the spring. Thousands of people are expected to line the procession route on the day of the wedding and we hope they will enjoy the bedding displays." New bedding will be planted in June.
Delamore and Thompson & Morgan offered 20,000 geraniums to replace the tulips, but Royal Parks said they would be dwarfed by the wallflowers.
British Protected Ornamental Association (BPOA) treasurer Simon Davenport said he was informed that red tulips in the Mall were losing petals due to the unseasonal hot weather and Royal Parks feared that they will be largely gone before the wedding.
However, Davenport said replacing them would prove to be difficult.