Dear Garden Problem Lady,

February 2019

743

Does cold winter weather stimulate dormant spring bulbs to grow roots?
No, autumn weather does that. We plant spring bulbs in the fall because the soil still holds summer’s warmth for a long time, encouraging root growth for perhaps two months before the ground freezes. As the sun wanes and temperatures fall, plants stop the spring and summer work of making leaves, shoots, flowers, berries, and fruit. All their energy goes into establishing roots, giving them a head start. Dormant bulbs begin making roots, which freezing does not kill – only halts their growth until the spring. Soil warms up slowly in spring, and for a shorter time, than the long waning warmth of the soil in autumn.

How do flowers bring water and nutrients up from the ground against gravity?
The botanical miracle you cite takes the technical vocabulary of a true botanist to explain. All plants have a complex circulation system in the cells of stalks, trunks and leaves, such that, at the cellular level, using tiny electrical charges among cells, they get water and chemical nutrients in soil to adhere to their stalks in chain-like formation, and rise upward

Is climate change affecting the temperature zone map of the United States?
The US Department of Agriculture has tweaked the Zone Map twice since the 1960s due both to climate change and also to better measurements. Some Northerly parts of the country morph lower slightly, and others roughly five degrees higher. Every individual garden also may contain “microclimates“– warmer or colder parts. In DC we are mainly Zone 7. Zone 3 is in Northern Montana and Maine. Zones 9 and 10 are in Texas, Florida and California. The Zone, referring to the average lowest temperatures of each zone, are important guides to planting.

 

At the February 12, 2019 meeting of the Capitol Hill Garden Club, Registered Horticultural Therapist Jan Lane will speak about using garden activities to improve cognitive ability and promote emotional well-being. The presentation highlights programs serving children’s hospitals, adults with developmental disabilities and community garden programs focused on emotional health. Meetings start with refreshments at 6:45 pm at the NE Public Library, corner of Maryland Ave. & 7th St. NE. Meetings are free and open to all. Membership details: capitolhillgardenclub.org.