Clematis ‘The President’ vs. ‘Jackmanii’ – How Do These Popular Varieties Compare?

Gardeners looking for beautiful flowering vines may find themselves deciding between two classic clematis cultivars – ‘The President’ and ‘Jackmanii’. Both are long-time favorites cherished for their large, elegant blooms in shades of rich purple. But there are some key differences between these two popular clematis that are worth understanding when making your choice.

First, a quick overview of clematis. Clematis are woody vines in the buttercup family, known botanically as Clematis spp. There are over 300 species and countless cultivars available. The vibrant flowers come in many colors like purple blue pink, red, white and bi-color. Blooms may be solitary or produced in clusters. Their blossoms are unmistakable with multiple layers of pointed petals and prominent yellow stamens.

Clematis vines can grow vigorously, reaching up to 10-20 feet high They perform best in full sun and moist, fertile soil The vines use their leaf stalks to climb up supports like trellises, fences and arbors. Hardy in USDA Zones 4-9, these are popular ornamental climbers in gardens worldwide.

Comparing Growth Habits

Now, lets compare some specifics of Clematis ‘Jackmanii’ and Clematis ‘The President’ related to their growth:

• Height – ‘Jackmanii’ grows slightly taller, typically 10-12 feet vs. 8-10 feet for ‘The President’.

• Spread – ‘Jackmanii’ has a wider spread of up to 4-6 feet across when supported. ‘The President’ reaches 3-5 feet in width.

• Foliage – They have similar foliage with opposite, pinnate medium green leaves. ‘Jackmanii’ may have a denser leaf cover.

• Hardiness – Both are cold hardy to zones 4-8. They can withstand winter temps down to -30°F when established.

• Pruning – These clematis bloom on old wood so prune lightly after flowering. Take out dead or damaged stems.

• Uses – Excellent for growing up trellises, fences, poles, walls and arbors. Also nice as a ground cover.

So in terms of their size, foliage and uses in the landscape, ‘The President’ and ‘Jackmanii’ are quite comparable. But when it comes to their blooms, there are noticeable differences.

Flower Size, Color and Abundance

The flowers are where these two popular clematis really stand apart:

• Flower size – ‘The President’ has larger blooms, 5-7 inches across. ‘Jackmanii’ produces smaller 3-4 inch flowers.

• Color – ‘Jackmanii’ is a rich royal purple, while ‘The President’ is a bluish-purple.

• Flower shape – Both have flowers with 4-6 petal-like sepals and pointed tips. However, ‘The President’ has more rounded, open flowers compared to the bell-shaped blooms of ‘Jackmanii’.

• Abundance – ‘The President’ is the more prolific bloomer of the two, often completely covering itself in flowers. ‘Jackmanii’ also blooms prolifically but its floral display is slightly less dense.

• Blooming season – They have similar long flowering seasons from early summer through fall.

So when weighed side-by-side, ‘The President’ offers larger, bluer blooms and greater profusion compared to ‘Jackmanii’. But either variety will provide a spectacular floral display.

Growth Rate and Care

You can also expect some similarities and differences in how fast these clematis grow and their care needs:

• Growth rate – They exhibit vigorous growth, adding as much as 3-5 feet of vines per year.

• Watering – Provide regular water during the first year to establish extensive root systems. Water as needed during droughts.

• Sun exposure – For the fullest flower production, plant in full sun. They will tolerate light shade.

• Soil – Grow them in moist but well-draining soil enriched with compost or manure. Neutral to alkaline pH is best.

• Fertilizer – Apply balanced fertilizer in early spring and again after flowering ceases.

• Support – Give them sturdy vertical supports to climb up. Tie in vines until they latch on.

• Hardiness – Although technically hardy to zone 4, protecting the roots in very cold winters can help overwinter them.

To keep them healthy and promote the most abundant blooms, ‘Jackmanii’ and ‘The President’ benefit from similar care practices. Just adjust watering and fertilization based on their size differences.

Tips for Planting and Training Clematis Vines

Here are some key tips for adding these showy clematis to your garden:

• Select a planting site with full sun to partial shade and fertile, well-draining soil. Amend if needed.

• Build a sturdy support structure at planting time. Use trellises, poles, wires or living supports like trees.

• Plant the vines 2-3 feet from their support to protect roots from excessive heat and promote vine branching.

• Wrap young vines around their support until they establish their leaf stalks for climbing.

• Prune carefully to remove dead or damaged stems. Otherwise, prune lightly after flowering ceases.

• Apply 2-3″ of mulch around the base to keep roots cool and maintain moisture.

Follow these best practices, and both ‘Jackmanii’ and ‘The President’ will thrive and reward you with billowing vines covered in showy blooms!

Two Clematis Classics Worth Growing

‘Jackmanii’ and ‘The President’ have long been cherished clematis varieties, gracing gardens for over a century. While they share vigor, hardiness and richly-colored flowers, ‘The President’ offers larger individual blooms and greater profusion on a slightly smaller vine. So weigh your specific needs – available space, desired flower attributes and more. With proper care, either of these timeless clematis will beautifully adorn vertical spaces as they cascade downward in floriferous displays. Any garden is lucky to host these flowering vine all-stars!