Rock Cress Vs Creeping Phlox [5 Major Differences]

Tiny flowers of Rock Cress that come in different shades might deceive you for Creeping Phlox. But it’s essential to know the difference, Rock Cress vs Creeping Phlox.

So, follow along to find the key difference between Rock Cress and Creeping Phlox.

Are Rock Cress And Creeping Phlox The Same?

Given the different family and botanical classifications, Ross Cress (Arabis spp) is not the same as Creeping Phlox (Phlox stolonifera).

But both plants have many common attributes, the first being their bloom color.

They add a pop of color to your garden. So they are often grown to attract pollinators like bees and butterflies.

Further, the other similarity is the low-growing habit of the plant. Rock Cress and Creeping Phlox stay close to the ground. So they are often used as ground cover to create a carpet-like effect.

Moreover, both plants have the potential to persist for more than a single growing season, owing to their perennial nature.

Rock Cress Vs Creeping Phlox: Major Difference

At first glance, it is common to mistake Rock Cress for Creeping Phlox, given their almost similar appearance, like how most confuse Dame Rockest and Phlox.

But with a closer look, you can decode the difference in leaf structure, flower, and growing habits between these biologically dissimilar plants.

1. Origin and Family

The major and only invisible difference between the Rock Cress and Creeping Phlox is their botanical classification and native region.

Rock Cress is a member of the mustard family, Brassicaceae. So, scientifically these Southern European and Asian native plants are the distant cousin of Wild mustard.

Meanwhile, Creeping Phlox, native to Eastern America, belongs to the Polemoniaceae.

2. Growth Habits and Spread

Despite both being low-growing perennials, Rock Cress and Creeping Phlox differ in compactness, with one being a little bushier than the other.

Although the Rock Cress makes it appear upright, Creeping Phlox is relatively more Creeping like its name.

It can spread up to 2 feet and form a dense mat of foliage in the garden.

On the other hand, Rock Cress has a clumping growth habit, so extending about 1 to 1.5 feet in its immediate surrounding takes time.

3. Foliage Morphology

Rock Cress has narrow, elongated leaves with lobed margins. The leaves are grey to bluish-green with a silvery dust appearance.

As for the Creeping Phlox, it has bright green needle-like leaves that are arranged in an alternate pattern along the stems.

But the actual difference is when you feel the plant. If the leaves feel smooth, soft, and fleshy, it is the Creeping Phlox. But the one with a fuzzy texture with tiny hairs on the surface is the Rock Cress.

4. Flower Appearance

Another distinction between Rock Cress vs Creeping Phlox is petal arrangement and flower size.

Creeping Phlox flaunts its five-petal flowers, usually in the spring. The flowers are relatively larger, 0.75 to 1.5 inches in diameter, with elongated petals often forming a star-like shape.

Unlike the above, Rock Cress has four petals, usually rounded or oval-shaped. The petals gather at the base to form a tube-like structure.

From afar, the blooming Rock Cress resembles a bunch of butterflies covering your garden.

5. Growing Conditions

Rock Cress and Creeping Phlox are drought-tolerant plants capable of surviving hot and dry summers.

However, light tolerance in Creeping Phlox is more than the others.

You can grow the Rock Cress from Zone 3 to Zone 7 without much problem.

But Phlox can barely make it beyond Zone 4 to Zone 9. So, use winter protection like a burlap cover or fleece blanket to protect your plant from winter extremities.