Developments on the site include a state-of-the-art 1,200sq m shop and a new 500sq m "Market Street" glasshouse.
Wombwell said: "It's great to see an independent garden centre flourishing and expanding despite the difficult economic times we have been experiencing."
The new shop replaces several old buildings at the front of the premises and has been built with under-floor heating to provide an improved shopping experience, reduce energy usage and fit in with traditional Essex barns in the area.
Alan and Karin Bourne took over Perrywood from Alan's parents 26 years ago. Alan said: "Customers who came to us in our early days may remember the original shop, which was a very long way from where the business is today.
"While we look very different our core values haven't changed, we've always put quality plants at the heart of what we do. Many of our plants are grown on the premises."
Now, Alan and Karin Bourne run the business with their 30-year-old son Simon. It employs 70 staff and has a 160-seat coffee shop. The latest development has been in the planning for three years. Malcolm Scott Consultants worked on the planning application.
Malcolm Scott planner Chris Primett said: "Perrywood and Wentworth (HW, 12 February) are good examples of well-run family businesses that create their own unique style, which some other garden centres could follow.
"They combine old and new buildings and show how you can evolve a business over time from retained earnings and create an attractive centre."