Philodendron 'Red Sun'

“Tree huggers” (Philodendron) are a diverse group of mostly climbing aroids (Araceae) from the Neotropics. There are also a few species that are reluctant to climb and grow creeping on the ground or even as a compact bush.

Due to their lifestyle, Philodendron are also called “nomadic climbers”. They usually start their lives on the forest floor, where they live as rather thin vines with poorly differentiated leaves and try to find a tree to climb. When they find a suitable substrate to climb, they attach themselves to it with special adventitious roots (similar to ivy) and grow up it. Only then do the leaves differentiate into their later adult form, and only then do they grow larger. After a few meters, many species also form so-called aerial roots, which, unlike adventitious roots, do not serve to attach to the substrate, but instead hang freely to the ground, providing the plant with additional nutrients. Often, after a few years and several meters of stem length, the lower part of the stem that connects the plant to the ground dies, and it is only in contact with the soil via its aerial roots. Now the plant lives as a so-called hemiepiphyte, or “semi-epiphyte”. In this way, nomadic climbers ascend large jungle trees over many years, finally reaching their maximum size and flowering in the tree canopy.

This lifestyle should be imitated (at least in part) in cultivation to obtain beautiful and healthy plants. Many Philodendron are easy to care for in indoor cultivation despite their unusual lifestyle.

This Philodendrongrows as a young plant in the shady undergrowth and as an adult plant in the much brighter canopies of primeval forest trees. With too little light and no climbing aid, it remains in its juvenile form and becomes leggy. Bright to very bright indirect light, e.g., next to a west or east-facing window or somewhat sheltered by a south-facing window, is ideal.

When cared for under grow lights, e.g., in a plant cabinet, terrarium, or grow tent, it needs quite strong lighting. It grows well at 5000 to 10,000 lux or 90 to 180 PPFD (µmol/m²/s).

Supplementary lighting to help it get through the dark winter months is very beneficial for this plant. Otherwise, it will produce significantly smaller leaves over the winter, which look unsightly overall.

This Philodendronlikes a humidity of 50% or more and still grows well even at over 90% RH. It is not sensitive to cool temperatures and can even tolerate night temperatures of 10°C, but it only grows well at 20°C or more.

This Philodendronprefers a coarse to very coarse, airy but consistently moist substrate. This plant should be potted in a loose, acidic (pH below 7) and very airy mix. For this plant, we recommend our Aroid Mixor, for larger specimens from 30 cm pot size, pure coconut chips.

The pot for this plant does not need to be particularly large. A pot that is too large will cause the substrate to be dry at the top but still wet at the bottom. This can lead one to think they need to water and thus drown the plant, which is actually still moist enough. Finding the right pot size requires some experimentation. As a guideline: if you can water every 5 to 10 days, and the substrate is almost completely dry ("iron-damp") in between, the size is well chosen.

This Philodendronclimbs and should be offered a climbing aid to show its natural growth. For this, you can either offer a coconut pole as a pure base for aerial roots or (better) a moss pole, filled with sphagnummoss or a mix of sphagnumand coconut chips. The moss pole not only serves as a climbing base but also offers the plant extra root space if the pole is kept consistently moist.

This Philodendron should never completely dry out, but how moist it likes to be depends heavily on the (substrate) temperature. Above 25°C, it can be kept consistently moist to wet. If it is kept as a houseplant (especially on a windowsill), it should be watered sparingly in winter, as the combination of colder temperatures and moisture weakens it and can lead to rot.

It is a fast-growing species that requires a lot of fertilizer. Fertilization should occur during the main growing season, from approximately May to September. If no additional lighting is provided, this plant will barely grow from October to April and does not need to be fertilized. No special fertilizer is required. A normal complete fertilizer (N-P-K + trace elements) for houseplants is sufficient. We recommend using the dosage specified by the manufacturer (which corresponds to about 1000 µS/cm conductivity for fertilizer).

When cared for under grow lights, it can be fertilized year-round.