Tips on Growing Gardenia Frostproof Plants

One of the most popular alternatives to roses out there is the Gardenia.

Gardenia jasminoides (gar-DEEN-ya jaz-min-OY-deez) is perhaps the most famous species boasting over a dozen cultivars. Check out these different types of Gardenias.

Flowering Frost Proof GardeniaPin

One of these cultivars is ‘Frostproof,’ which allows homeowners to enjoy the cape jasmine in colder climates.

Much like its Southeast Asian parent, ‘Frostproof’ is an evergreen perennial known by several names, including:

  • Cape Jasmine/Jessamine’ Frostproof’
  • Common gardenia ‘Frostproof’
  • Frostproof Gardenia

As a member of the Rubiaceae family, ‘Frostproof’ has quite a few relatives, including more than 140 in the Gardenia genius alone.

These plants require moderate care and will usually tolerate a small amount of neglect if done infrequently. More on Gardenia Plant care.

Gardenia Jasminoides’ Frostproof’ Care

Size & Growth

Gardenia’ Frostproof’ can reach a size of 5′ feet tall and 4′ feet wide.

It has rich green leaves that make the plant visually appealing even when not in bloom.

Fragrant Flowers

As with other gardenias, ‘Frostproof’ begins with continuous blooming in early summer throughout the season.

It produces showy, white blooms measuring an impressive 3″ inches across.

The fragrant flowers not only contrast beautifully with the plant’s foliage but produce a sweet, heady scent.

Light & Temperature

Adequate sunlight is essential if you want plenty of blooms, so pick a spot with full sun to light shade.

Ideally, the plant will have full morning sun and afternoon shade when grown in hotter climates.

In cooler climates, a well-mulched ‘Frostproof’ will enjoy full sun all day long.

The main draw of ‘Frostproof’ is its slightly higher frost tolerance, allowing it to be planted in USDA hardiness zones 7 to 10, whereas normal cape jasmine has a range of zones 8 to 11.

When grown in containers, this plant may be grown in even colder zones and brought in as the temperature drops.

Watering and Feeding

Water your cape jessamine ‘Frostproof’ regularly, ensuring the soil stays consistently moist but not too wet.

‘Frostproof’ has a high iron requirement, so feeding is a necessity.

Give one feeding of an extended-release azalea or gardenia fertilizer after the final frost, with a second dose six weeks later.

The fertilizer should have a 2-1-1- NPK ratio.

Yellowing of the plant’s leaves means it isn’t getting enough iron, which may be further supplemented during the summer, applied according to the supplement’s packaging.

Soil & Transplanting

‘Frostproof’ prefers moist, well-drained, and organic-rich soil.

That said, it will grow in loamy, sandy, or even clay-like soils as long as the latter is appropriately amended with coarse sand or lava stones to improve drainage.

Aim for a soil pH between 5 and 6.5 and ensure minimal salt content, as these plants have a very low salt tolerance.

Mulching with 2 to 3″ inches of bark or pine straw will have a big effect on the plant’s health.

You will need to pay attention to spacing, giving these plants a 48 ” inch berth further.

Despite having better frost tolerance, ‘Frostproof’ has very delicate roots, which may actually be damaged if they have to compete with neighboring plants.

Transplanting is similar to that of other gardenias, although extra care must be taken when handling the roots.

Make sure the plant is in good health before attempting to transplant or repot, as gardenias don’t like being moved.

In late summer, prune the plant back by ¼ to ⅓ and allow it to heal for one week before beginning the transplant.

Prepare the new location (either ground or a new container one size larger) prior to uprooting the plant.

Next, dig around the plant, being careful to excavate far enough out to avoid harming the roots.

You will want to transplant the root ball with as much of the original soil as possible, which is admittedly easier with a container plant.

Once lowered into its new spot, gently backfill the remaining space and tamp the area down.

Water thoroughly and add some more water every other day over the following week to help ensure the new and old soil blend and the roots are able to start spreading out.

Grooming And Maintenance

Grooming can be highly beneficial to your ‘Frostproof’ but is most commonly done for the sake of shaping.

Deadheading just below the leaf node will help encourage further blooms.

It should be pruned after the end of its blooming period and before the fall.

Avoid hard pruning, which can stunt the plant’s growth the following year.

How To Propagate Cape Jessamine’ Frostproof’

Propagating ‘Frostproof’ is easiest using stem cuttings.

You’ll want to remove 3 to 4″ inches of a stem tip early in the spring, making sure to cut just under a leaf node.

Dip your cuttings in root hormone and embed them in a pot of Gardenia potting mix.

Keep the soil and do a gentle tug test after about a month to ensure the cuttings have rooted.

Once you confirm root growth, the plants may be moved to 3″ inch pots.

It’s also possible to propagate using seeds, although this method tends to be a lot more difficult to master.

You will need to dry the seed pods for one month before harvesting the seeds.

Plant these ¼” inch deep in a mix of peat and perlite and sit the trays somewhere sheltered from direct sunlight.

Keep the soil moist until the seeds have germinated, which takes as long as 4 to 6 months.

Once the seedlings are several inches tall, you may transplant them to pots containing a peat-based potting mix.

Gardenia’ Frostproof’ Pests or Diseases

‘Frostproof’ is surprisingly durable overall, with resistances to many common diseases, deer, drought, heat, and mildew.

Iron deficiency is one of the most common problems this plant faces, resulting in yellowed foliage. Details on the cause and treatment for yellow leaves on Gardenia.

Leaf spot may also occur if too much water ends up on the leaves.

Improper watering can result in bud drop.

Despite better disease resistance, this plant may suffer from infections, such as Anthracnose, powdery mildew, and sooty mold.

‘Frostproof’ is also vulnerable to Gardenia aphids, mealybugs, scale, spider mites, and whiteflies.

More on Gardenia Pests here.

Cape Jasmine ‘Frostproof’ Uses

This beautiful plant is perfect for borders and hedges.

It also fares well in containers and may even be planted in large containers with smaller plants that won’t compete for root space.

It plays very well with a number of other attractive plants, including:

The flowers and their wonderful scent make great bouquets.

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