The Little Asparagus that Could

In 2006, NC plantsman, and our long time customer, Graham Ray of Greensboro, emailed to see if we were interested in a dwarf Asaparagus densiflorus (Sprengeri) fern that he grew in his rock garden, and had been winter hardy for several years in his Zone 7a garden.

We had already worked with several asparagus species for years, and have a great fondness for the ornamental potential of the genus, so of course, we jumped at the opportunity. We were perplexed, however, how a dwarf version of the marginally hardy Asparagus densiflorus could have survived in Greensboro, which is a 1/2 zone colder than our garden south of Raleigh.

Despite our skepticism, we planted our new treasure in fall 2006, which thrived here, despite our winter hardiness concerns, not blinking during three upcoming single digit F winters. A few years later, we sent a plant to our friend Hans Hansen at Walters Gardens in Michigan for further testing. Despite their winter temperatures well below 0F with no snow cover, it thrived there also. What was going on, we wondered, since this simply shouldn’t be possible.

A mature plant of the dwarf asparagus fern, 'Graham's Cracker' growing in our rock garden.
Asparagus ‘Graham’s Cracker’

Our mystery was finally resolved this summer when taxonomy researchers from the University of Georgia, working on the phylogeny of the genus Asparagus, learned of our extensive collection of Asparagus species, and came by to take samples for their research. This fall, we got word that our dwarf plant which we had named Asparagus ‘Graham’s Cracker’, was in fact not a selection of the common hanging basket species, Asparagus densiflorus, but was instead a seedling of the Zone 4 hardy Asparagus cochinchinensis.

As we re-traced the plants origin, it turned out that Graham had purchased the plant here at Plant Delights, as a dwarf seedling he found in one of our sale house flats, which our staff had failed to notice.

Above is a photo of a mature plant of Asparagus ‘Graham’s Cracker’ at JLBG, which has finally reached a whopping 15″ in height…a perfect plant for the rock garden or in larger bedding schemes. Like the species, the fall foliage is a brilliant gold.

Asparagus ‘Graham’s Cracker’ in fall

And here’s mama, Asparagus cochinchinensis ‘Chuwang’.

Asparagus cochinchinensis ‘Chuwang’

Act Like a Tree and Leave

We all love the color of leaves in fall…at least until they need to be raked. Here are a few that we enjoyed at JLBG recently.

Acer triflorum ‘Aureum’ really put on a lovely show with leaves that held on quite a while. It also colored later than most other maples.

Acer triflorum ‘Aureum’

Euonymus carnosus was quite stunning, although the effect really didn’t show up as well in the photo.

Euonymus carnosus

Parrotia persica is one of the last deciduous trees to color and drop in our garden. The typical color is yellow, although I’ve seem some pretty amazing red-leaf forms as well. We have not noticed much in the way of color on Parrotia persica ‘Vanessa’.

Parrotia persica

Parrotia subaequalis is the star of the genus when it comes to fall foliage, which is a brilliant purple red.

Parrotia subaequalis Ogisu clone

Although our row of Metasequoia ‘Ogon’ turn brown in fall, it’s still an amazing show. These are the oldest plantings of this cultivar in the US.

Metasequoia glyptostroboides ‘Ogon’

Solomon’s going to sleep

Here are few images of our Solomon’s Seal (polygonatum) going to sleep in the garden. We think they are fascinating even as they approach dormancy. The top image is Polyongatum falcatum showing the amazing fruit set contrasting with the aging foliage.

Polygonatum falcatum with aging foliage
Polygonatum falcatum

The next image is Polygonatum odoratum, which probably has the best golden fall color of any species we’ve observed. At bottom is Polygonatum involucratum showing the transformation of the involucres (the pouches that hold the flower), and they age to tan, prior to the leaves changing colors. Solomon’s seal are cold hardy from zones 4 to 9.

Polygonatum odoratum with golden fall foliage
Polygonatum odoratum

Solomon's Seal showing the transformation of the involucres
Polygonatum involucratum

Falling for Ginkgos

Gardeners typically curse fall leaf drop, but ginkgo trees often get a pass, not only because the golden fall leaves look so great on the tree, but they also look great on the ground, not displaying the disheveled look of other larger tree leaves. Here’s our ginkgo tree, planted just in front of our office, that’s been putting on quite a show for the last few weeks.

Ginkgo trees are know for their brilliant golden yellow fall color.
Ginkgo biloba

Despite what most folks think, the genus Ginkgo is indeed a North American native, but to understand that, requires a bandwidth that many native plant purists simply don’t have. Native is not a place in location, it is only a place in time. The first Ginkgos date back to the lower Jurassic period about 190 million years ago, when the genus was born in Mongolia. From there, it migrated around the world, based on dramatic climate change, with fossils found from what is now the UK to the US (Oregon to North Dakota).

Ginkgos continued to diversify through the Cretaceous period (65-145 million years ago), when they reached their maximum distribution, with 5-6 species currently recognized. By the Paleocene (56-66 million years ago), all of the species but one had gone extinct. Although that remaining species is known as Ginkgo adiantoides, it is almost identical to today’s Ginkgo biloba.

During the Oligocene (23-34 million years ago), Ginkgos moved south from their more northerly range, with the genus completely disappearing from North America around 7 million years ago. According to the fossil records, Ginkgos subsequently disappeared from Europe around 2.5 million years ago. The only vestiges of the genus that remained, holed up in three distinct refugia (botanical hideouts) in China until humans began to spread them out again and re-populate the rest of the now Ginkgo-less world. They returned to the Flora of both North America and Europe in the 1700s.

For those who want to dive deeper into the Ginkgo story, here is a link and another.

When Ginkgo trees are ready to shed their leaves, they normally do so within a day.
Ginkgo biloba