Monstera deliciosa 'Thai Constellation'

While classic monstera varieties are easy (and fairly affordable) to come by at any plant nursery, these popular houseplants become extremely coveted and expensive once specialty cultivars and defects come into play.

One of the most sought-after at the moment is a varietal called the 'Thai Constellation' which features the signature white patterns on its leaves caused by lack of chlorophyll, in this case in a splatter pattern.

The 'Thai Constellation' will go for more than the 'Variegata'. Depending on the specimen and the size, it can cost several hundred dollars to upwards of $1,000, Summer Rayne Oakes of Plant One on Me shares with us.

Oakes adds she's seen cuttings go for as much as $300 to $500!

"People in general love Monstera, as it's one of those larger leaved plants with deep fenestrations," Oakes says. "But you add spatter-marked whites and yellows to the leaves—and it'll drive the price up quite readily."

Monstera deliciosa Albo Variegata

However, the 'Thai Constellation' isn't only one Monstera deliciosa variety that's considered rare and valuable.

The 'Albo Variegata,' which features large white portions on its leaves, the more and the more unique in shape and structure the better, is also going for hundreds of dollars in many shops.

"Variegated Monsteras are a top seller, which are around $200, but we've seen them go for much more than that depending on the color of their leaves," Sean Dollinger, Founder of PlantX, says. "The whiter the leaves, the more coveted they are based on a rare genetic defect."

Philodendron Melanochrysum

Slowly becoming slightly easier to come by, this variety is still considered one of the rarer and more coveted philodendrons in the houseplant community, and can be expensive, especially when reaching larger sizes.

When given proper light conditions and extra humidity, these dark green beauties can climb up to 5 feet tall indoors, with individual leaves reaching massive sizes of 2 feet long.

These huge healthy specimens will be rarer and harder to find, so if you're able to nurture a small philodendron melanochrysum into a massive houseplant over time, all the better.

Philodendron Tortum

Philodendrons come in many varieties, from the highly common and budget-friendly, to the ultra-rare collector species. This is another type that can break the bank, and be difficult to find.

They're very eye-catching, with their spreading, spike-like leaves. But they also differ from some of their philodendron relatives in their care needs. Philodendron tortums need extra space to spread, grow quickly, and do well with high humidity.

Philodendron 'Pink Princess'

One final philodendron variety is a natural inclusion on a rare houseplants list. The Pink Princess is as lovely and unique as its name suggests, and is a man-made cultivar developed in the 1970s.

Single cuttings of this plant can cost upwards of $100 and mature healthy plants can cost several hundred.

Pseudolithos cubiformis

This uniquely shaped succulent isn't one you're likely to come across at your average plant store. Its cube-like shape and scaly texture are unusual in the world of houseplants and succulents, and make it desirable in the plant collector world.

But, this plant's slow-growing cycle and complex care needs make it even rarer to come across.  

"Typically, the smallest specimens will go for $75 to $125," Oakes says.

Anthurium regale

Anthuriums are another common houseplant you can find in many casual collections—but its larger and more stately variety, the Anthurium regale, is a much rarer and much more expensive addition to any collection.

With small young plants priced at $100 or more and large, full-grown Anthurium regales costing upwards of $400, it's a spendy, but stunning plant to bring home.

Aglaonema pictum 'Tricolor'

With leaves that feature a uniquely mixed look of light, medium, and dark green shades, it's not too surprising that this Aglaonema variety is sought after.  

"The camouflage appearance of the leaves makes it a real crowd-pleaser," Oakes says.

While considered fairly easy to grow, they also grow slowly, which increases the difficulty of coming across one of these eye-catching beauties.  

"Aglaonema cannot be reproduced successfully through tissue culture," Oakes says, "So there aren't many of these on the market, which drives up the price,"

Oakes says she purchased her back in 2016 for only $39. Nowadays, she's seen some people pay somewhere between $100 to $200.

Anthurium regale

Anthuriums are another common houseplant you can find in many casual collections—but its larger and more stately variety, the Anthurium regale, is a much rarer and much more expensive addition to any collection.

With small young plants priced at $100 or more and large, full-grown Anthurium regales costing upwards of $400, it's a spendy, but stunning plant to bring home.

Planthub Petunia Flower Seeds

Planthub Petunia Flower Seeds, Dwarf Grandiflora Mixed, Petunia Nana Compacta - Pack of 200 Seeds.

Acanthus mollis

Acanthus mollis, commonly known as bear's breeches, sea dock,[2] bear's foot plant, sea holly, gator plant or oyster plant,[3] is a species of plant in the family Acanthaceae  and is native to the Mediterranean region. It is a leafy, clump-forming perennial herb, with a rosette of relatively large, lobed or toothed leaves, and purplish and white flowers on an erect spike.

Agapanthus 'Blue Storm' (Lily of the Nile)

Plant these en masse for maximum impact. The flowers are more much numerous but much less tall (to 4ft max) than in the huge and better known Agapanthus africanus. Drifts of them work wonders. The clue's in the name - it's an enormous amount of blue. It's also hardier than Agapanthus africanus but dies down in the winter. Flowers for several weeks during mid-summer.

Best in sun in any reasonably well drained soil.

A comparative comment on Agapanthuses : The big one (Agapanthus africanus) and the little ones (Agapanthus 'Blue Storm' and 'Snow Storm') cannot really be compared. It's tempting because they're both Agapanthuses and they both have green strappy leaves and either blue or white flowers but the big one stands alone and are so big that they can be used almost like topiary - a pair in pots either side of an entrance for example. There's no reason why you couldn't do the same with the smaller ones but the smaller ones really lend themselves to being planted in drifts - blue or white rivers wending their way through the garden. The point is, one's not comparing like with like.

ACANTHUS MOLLIS (BIG SPINACH)

Bright green, leafy perennial, fully hardy and evergreen in mild areas. Will grow to about 3-4ft tall and across. Easy plant to cultivate. Acanthus will grow in sun or shade. It'll flower more in the sun but the leaves will look bigger and darker and shinier in the shade. The tall spikes (6ft ish) of purple-hooded white flowers appear in high summer. The carved leafy bits so characteristic of the capitals on Corinthian columns are they. Not surprising really as Acanthus grows everywhere around Corinth and evidently did 2500 years ago too.

Removal of old flowers and leaves (anything unsightly) is a great help - especially in winter. Severe frost (-4°c or below) will give the leaves a look that could be described as both glazed and floppy. It can look terminal but it's not. They recover wonderfully well as soon as the temperature rises.

PLEASE NOTE : this plant is occasionally susceptible to powdery mildew, an endemic  air-born fungus. It's easy to treat and we suggest the following action can be taken if you see the white powdery residue on the leaves. Remove as much of the affected parts as possible; clean up thoroughly and remove all rubbish from the area; spray with a general purpose ready to use systemic fungicide - one that contains myclobutanil - such as Fungus Fighter. Easy to cure. Alternatively, just remove ALL affected leaves and burn them.

Anthurium regale

Anthuriums are another common houseplant you can find in many casual collections—but its larger and more stately variety, the Anthurium regale, is a much rarer and much more expensive addition to any collection.

With small young plants priced at $100 or more and large, full-grown Anthurium regales costing upwards of $400, it's a spendy, but stunning plant to bring home.