Aquatic Plant Design on Display at Denver Botanic Gardens

Published on December 28, 2021

water garden waterlilies
Victoria ‘Longwood Hybrid’ is displayed with Canna ‘Bengal Tiger’ and a variety of waterlilies at the Monet pool.

As the horticulturist who cares for the aquatic plants here at Denver Botanic Gardens, I am lucky to have a large variety of ponds to work in. More than half a million gallons of water recirculate through the main waterway at DBG, connecting a wide array of terrestrial gardens throughout our 24-acre property. In addition, smaller standalone water features can be discovered tucked away in other areas of the gardens, ensuring that visitors are never far from the soothing splash of a waterfall or the sight of a pond brimming with colorful waterlily blooms.

During these colder winter months, much of my time is spent designing the aquatic plant displays for the coming season. Part of that process for me is looking at photos of previous years’ displays to evaluate what did well, what could be improved and which new plants should be added to the collection. Each pond’s display is created to not only highlight specific aquatic plants, but also to blend with the gardens surrounding that particular pond. 

If you’re like me, looking at photos of plants in all their summer glory also provides a dose of horticultural therapy that is much needed during this time of year. So, I invite you to join me on a photographic walking tour of the water gardens at DBG to look back on displays of years past — and to plan for the coming season!

Ellipse Garden Pool

Beginning at the entrance to the gardens and strolling south through our perennial walk, Chihuly’s “Colorado” sculpture can be seen towering in the distance. This piece of art was created with orange, red and yellow pieces of glass and sits in the center of a small ellipse-shaped pond. 

Nelumbo ‘Aoyun Lian’ (Olympic Lotus) bloom.

I like to use shorter marginal plants in this pond to avoid taking away from the sculpture’s impressive height and structure. Petite plants such as Canna‘Chiquita Punch’ or Canna ‘Lemon Punch’ and Colocasia ‘Black Magic’ complement the sunset shades of the glasswork nicely. I also love the foliage of Canna ‘Bengal Tiger’ but found that it got a bit too tall for the space. 

Mosaic plant (Ludwigia sedioides) thrives in the warmer water of a small pool and fits into the color palette with its tiny green leaves and bright-yellow blooms. Hardy waterlilies such as Nymphaea ‘Wanvisa’, ‘Joey Tomocik’ and ‘Manee Red’ are also favorites, along with a tropical waterlily with blooms that blend well with the color scheme (such as ‘Stan Skinger’ or ‘Tropic Sunset’).

Romantic Garden Pool

Continuing west from the Ellipse Garden, we arrive at the Romantic Garden, where a formal round pool displayed a colorful array of “star waterlilies” this past summer. These tropical day-bloomers boast star-shaped flowers that are held high above the water’s surface. Hybrids displayed included Nymphaea ‘Rhonda Kay’, ‘Carnea’ (syn. ‘Orchid Star’), and ‘Rhapsody in White’. Night-blooming water platters (Victoria ‘Longwood Hybrid’) surrounded a recirculating fountain in the center of this pond and were a hit with visitors. 

A display dedicated to taro (Colocasia esculenta and hybrids) has been featured the past few summers in the next small pond downstream and to the west of our Steppe Garden. These water-loving marginal plants are commonly grown for their starchy edible corms.

This year, I would like to swap in Victoria cruziana for the center of the pond and display an assortment of Australian waterlilies around the perimeter.  Since the pond is smaller in volume, the water stays an average of 8 to 10 degrees warmer than it does in our large waterway, making it an ideal spot to grow these often finicky waterlilies. I also hope to get this pond heated in the future, with the goal of growing the heat-loving Victoria amazonica to blooming size. 

Four Towers Pond

Nymphaea ‘Detective Erika’
Nymphaea ‘Detective Erika’ is an intersubgeneric hardy x tropical cross from Zijun Li of China.

Directly west of the Romantic Garden, the Four Towers Pond borders our Science Pyramid on two sides. Intersubgeneric hardy x tropical waterlilies were displayed at the east end of this pond last summer. Once thought to be an impossible cross, multiple hybridizers have now successfully created these hybrids, which boast purple or bright magenta flowers on winter-hardy plants. Many of the cultivars in our collection, including ‘Detective Erika’, ‘Purple Fantasy’ and ‘Siam Purple 1’, were donated to us by hybridizers after the conclusion of the International Waterlily and Water Gardening Society’s New Waterlily Competitions when we served as the growing site from 2012 to 2015. 

Continuing around to the west side of the pond, I like to use a variety of taller marginal aquatic plants in the center portion of the pond running in a line from north to south. A mix of hardy and tropical waterlilies are placed to the east and west of these taller plants, allowing for visitors to enjoy them from the sidewalk and the windows of the Science Pyramid. I usually also include Victoria ‘Longwood Hybrid’ plants in this display. 

Last summer, I used marginal plants, including Canna ‘Blueberry Sparkler’, Thalia geniculata and Hibiscus moscheutos hybrids along with the fine texture and bright variegated foliage of Phragmites australis ‘Aurea’. This year, I plan to change the design and use Thalia geniculata f. ruminoides along with Canna ‘Tony’ and some groupings of Cyperus prolifer and Acorus gramineus ‘Aurea’. It’s always fun to play with new plant combinations!

Reflections Pool

A display dedicated to taro (Colocasia esculenta and hybrids) has been featured the past few summers in the next small pond downstream and to the west of our Steppe Garden. These water-loving marginal plants are commonly grown for their starchy edible corms. Many hybrids have also been developed for ornamental use and have leaves that range from deep, glossy black (such as ‘Diamond Head’) to chartreuse with splashes of deep purple (like ‘Mojito’). 

Colocasia esculenta
A display of taro (Colocasia esculenta and hybrids) in the Reflections pool

Last summer, I also used a mix of hardy waterlilies in this pool surrounding the stone sculpture titled “Reflections.” This year, a few tropical lilies will be added to the display to prolong the bloom season in this feature.

Annuals Garden 

Nymphaea ‘Wanvisa’,
Nymphaea ‘Wanvisa’, a hardy waterlily with variable flowers

Hardy and tropical waterlilies in the Rocky Mountain Legacy Collection (RMLC) are displayed in the pools downstream and adjacent to our Annuals Garden. This waterlily collection includes cultivars such as ‘Joey Tomocik’, ‘Colorado’, ‘Denver’s Delight’ and ‘Denver’, which were all tested for hardiness and performance in Denver’s unique climate and named by DBG’s former curator of aquatics, Joe Tomocik. Tropical lilies including ‘Stan Skinger’ and ‘William McLane’ round out this collection. I added marginal plants including White Rush (Schoenoplectus ‘Albescens’), Canna ‘Belinda’, Canna ‘Summer Breeze’, Lobelia ‘Pacific Beauty’ and Hibiscus moscheutos ‘Cherry Cheesecake’ to these ponds last season. 

This year, I would like to keep the RMLC in these ponds, but I would like to swap in different marginal plants after consulting with our horticulturist who maintains the annuals garden. I like to coordinate with the colors she’s chosen, since the annual beds provide the backdrop to these displays. Another consideration that is fun to design around is the “Zen Doorway” sculpture located in the east pool. I often use marginal plants on each side of this sculpture and a waterlily centered in front of and a few feet behind the opening so that they appear to be framed when viewed from a distance.

Monet Pool

Heading west from the Annuals Garden, we arrive at our largest display pond, the Monet Pool. Victoria ‘Longwood Hybrid’ waterlilies encircled a large red-stemmed Thalia in the center of the pond in previous years. I like to keep the Victoria plants on this east side of the pond in the center of the display, mostly to avoid the inevitable shower of gravel on the pads that occurs if they are placed too close to the edge. I’ve learned that rocks and water are an irresistible combination for kids, and our adjacent Plant Select Garden uses fine gravel as mulch. I usually display a couple of Victoria plants on the far west side of this pond, where rocks and gravel are harder to find nearby.

The Monet pool features a wide variety of waterlilies and marginal plants.

A wide variety of hardy and tropical waterlilies and marginal plants, including lotus (Nelumbo hybrids), are displayed in this pond each year as well. The lotus are located near the entrance walk to our Japanese Garden, and one large grouping is placed right at the pond’s edge for visitors to get up close to admire the impressive blooms, seed pods and leaves. We often also move hardy or tropical waterlilies closer to the edges of the pond as they come into peak bloom. Hardy waterlilies are highlighted earlier in the season (June and July) and tropical waterlilies in August and September. We have made hooks out of modified irrigation keys that make it easy for us to drag the planting containers wherever we want without straining our backs.

Nymphaea ‘Manee Red
Nymphaea ‘Manee Red’ is a hardy waterlily from hybridizer Pairat Songpanich of Thailand.

I also enjoy creating small groupings of plants in this pond to play with color, height and texture combinations. One of my favorite combinations this past summer in the Monet Pool had Cyperus papyrus at the back of the grouping with Canna ‘Bengal Tiger’ beside it and Colocasia‘Diamond Head’ in front, and finished off with the tropical waterlily Nymphaea ‘Foxfire’ in the foreground.

Our tour comes to an end at a small pond that sits in the middle of our Le Potager (kitchen) garden. Edible aquatic plants are displayed in this pool to fit with the theme of this area. Lotus (Nelumbo nucifera), water chestnut (Eleocharis dulcis), gorgon plant (Euryale ferox), Santa Cruz waterlily (Victoria cruziana), ornamental rice (Oryza sativa ‘Black Madras’) and taro (Colocasia esculenta) have been highlighted in this pond. This year, I plan to expand this collection to include our North American native lotus, Nelumbolutea, as well as our native Rocky Mountain pond lily, Nuphar lutea ssp. polysepala.

I hope this tour through our water gardens at DBG has you looking forward to the summer months ahead. And once they arrive, I hope that you will have the opportunity to visit us in person to see all our aquatic plants and planting designs in their full glory!

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