Origin
Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén, also known as Porsild's saxifrage, is a plant native to the Arctic regions of North America, including Alaska, Canada, and Greenland. It grows in rocky or gravelly areas and can withstand harsh cold temperatures.
Common Names
Porsild's saxifrage is known by various common names, including Nelson's saxifrage, creeping saxifrage, Porsild's rockfoil, and Arctic Saxifrage.
Uses
Indigenous peoples of the Arctic have traditionally used Porsild's saxifrage for medicinal purposes, including treating respiratory ailments and as a source of vitamins. The plant is also used for ornamental purposes due to its delicate, petite appearance.
General Appearance
Porsild's saxifrage is a low-growing perennial herb that typically grows to a height of 5-15 cm. The plant has a creeping habit with thin stems that root at the nodes. The leaves are small and leathery, and the flowers are borne on short stalks that rise above the foliage. The flowers are small, usually pink or white, and have five petals that are slightly notched at the tip. Porsild's saxifrage blooms in early summer, and the plant produces small, spherical seed capsules in late summer.
Light Requirements
Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén typically grows in areas with bright to moderate light. In its natural habitat, it can be found growing in rock crevices, slopes, and alpine meadows that are exposed to direct or partial sunlight. As such, it is best to place this plant in a well-lit area that receives at least 6 hours of sunlight a day.
Temperature Requirements
This plant is native to arctic and alpine regions, and it is adapted to withstand cold temperatures. It can tolerate temperatures as low as -34°C (-30°F). However, it can also grow in more moderate temperatures, ranging from 15°C to 21°C (59°F to 70°F) during the growing season. It is important to note that this plant requires a period of winter dormancy, where temperatures should be consistently below 10°C (50°F) for about 3 to 4 months.
Soil Requirements
Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén has specific soil requirements. The soil should be well-draining and have a pH ranging from 6.0 to 7.0. It prefers soils that are rich in organic matter and can hold moisture well, but not waterlogged. Sandy loam soil or rocky soil with good drainage is ideal for this plant. It is also important to note that this plant is sensitive to high levels of salts in the soil, so it is best to avoid using fertilizer or compost that is high in salts.
Cultivation Methods
The Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén primarily thrives in rocky, well-draining soil in alpine and subalpine habitats. When grown in gardens, it can tolerate a wide range of soil types, but the soil should be amended with sand or gravel to improve drainage. Planting in a raised bed or rock garden is ideal to replicate its natural habitat. The plant prefers full sun to partial shade and can tolerate low temperatures.
Watering Needs
The plant prefers moist to dry soil conditions. Overwatering can lead to root rot and other fungal diseases, so it is best to allow the soil to dry out between watering. During prolonged dry spells, regular watering can help the Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén maintain its vigor.
Fertilization
Fertilization should be done in the spring when the plant starts actively growing. Use a balanced fertilizer with an N-P-K ratio of 10-10-10 or lower. Follow the manufacturer's instructions to avoid over-fertilizing. Too much nitrogen can promote excessive leaf growth at the expense of flower production.
Pruning
Pruning is not necessary for Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén, but deadheading old flowers can promote a longer blooming period. Remove damaged or diseased foliage to improve the plant's overall appearance and prevent the spread of diseases.
Propagation of Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén
Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén can be propagated by different methods such as division, cuttings, and seed sowing. The most common and successful propagation method is seed sowing.
Seed Sowing
Propagation of Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén by seed sowing can be done indoors in early spring or outdoors in a prepared bed in late fall.
First, moisten the soil mix and fill the containers, leaving some space at the top. Sow the seeds evenly on the surface and then lightly cover them with a thin layer of soil mix or vermiculite. Finally, water the container and cover it with a plastic bag or lid to maintain moisture and humidity.
Keep the containers in a bright and cool place, around 15-20°C, and monitor the soil moisture regularly. The seeds should germinate in approximately two to four weeks. Once the young plants have emerged, remove the plastic lid or bag and move the containers to a brighter location. Water the seedlings sparingly and feed them with a weak liquid fertilizer solution every two weeks.
The seedlings can be transplanted into their permanent location once they have developed their second or third set of leaves.
Division
Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén can be propagated by division in early spring or fall.
To propagate by division, carefully lift the plant and separate it into smaller sections, ensuring that each section has some roots attached. Replant the smaller sections into their permanent location in well-draining soil mix.
Cuttings
Propagation by cuttings is possible, but it's not a common method for Saxifraga nelsoniana D. Don ssp. porsildiana (Calder & Savile) Hultén.
To propagate by cuttings, take a 3-5cm long stem cutting from the plant's new growth in early summer. Remove all the lower leaves and dip the cut ends into rooting hormone. Plant the cuttings in a pot or tray filled with a moist soil mix and cover them with a plastic bag or lid to maintain humidity.
Place the cuttings in a bright location, away from direct sunlight, and keep the soil moist. The cuttings should root in approximately four to six weeks. Once the cuttings have established roots, transplant them to their permanent location in well-draining soil mix.
Disease Management
Saxifraga nelsoniana D. Don ssp. porsildiana is susceptible to bacterial, fungal, and viral diseases. Some of the common diseases that might affect this plant are:
- Crown and Root Rot: Caused by Pythium, Phytophthora, or Rhizoctonia fungi, this disease can cause wilting, stunted growth, and eventually death of the plant. To manage this disease, avoid overwatering and improve soil drainage. Fungicides can also be used.
- Powdery Mildew: This fungal disease causes a white, powdery growth on leaves and stems. It can be managed by removing infected plant parts, watering in the morning instead of evening, and applying fungicides.
- Virus infections: Virus infections cause discolored patches, distorted growth, and reduced yield. Infected plants must be removed and destroyed to prevent the spread of the virus.
Pest Management
Saxifraga nelsoniana D. Don ssp. porsildiana is also prone to insect and mite infestations. Some common pests that might affect this plant are:
- Aphids: Aphids suck plant sap and can cause distorted growth and yellowing of leaves. They can be removed by washing the plant with a strong jet of water or by applying insecticidal soap.
- Spider mites: Spider mites feed on plant sap, causing yellowing and mottled leaves. They can be managed by keeping the plant well-hydrated, removing infested plant parts, and applying miticides.
- Thrips: Thrips cause deformed flowers and leaves, and can transmit viruses. They can be controlled by applying insecticidal soap or using yellow sticky traps.
